CVE-2026-121373 (GCVE-0-2026-121373)

Vulnerability from cvelistv5 – Published: 2026-11-04 12:59 – Updated: 2026-11-04 18:20
VLAI
Title
Symfony: HtmlSanitizer MetaRefreshAttributeSanitizer Matches Only a Narrow Subset of the Browser Refresh Grammar (Incomplete Fix for CVE-2026-48761)
Summary
The Symfony HtmlSanitizer component MetaRefreshAttributeSanitizer, introduced to fix CVE-2026-48761, sanitizes the refresh URL of content attributes of meta tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11. The shared declarative refresh steps in the WHATWG HTML Standard require a broader approach: the separator after the time may be ASCII whitespace alone, with no ; or ,, and the url= keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips UrlSanitizer entirely and both allowLinkSchemes and allowLinkHosts are defeated for the refresh navigation. This is reachable under any configuration that allows meta with http-equiv and content, including the documented allowStaticElements() preset.
Severity
5.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-11-04 17:49 UTC
CWE
  • CWE-186 - Overly restrictive regular expression
  • CWE-601 - URL redirection to untrusted site ('open redirect')
Assigner
Checkmarx CNA under the mitre root
CNA scorecard B 88/100 over 23 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
sensiolabs symfony Affected: 6.1.0 , < 6.4.50 (git)
Affected: 7.0.0 , < 7.4.23 (git)
Affected: 8.0.0 , < 8.1.11 (git)
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
    cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Ilia Alshanetsky Nicolas Grekas
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-121373",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-11-04T17:49:00.814730Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-11-04T18:20:22.620Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://packagist.org/packages/symfony/html-sanitizer",
          "defaultStatus": "unaffected",
          "modules": [
            "Symfony\\Component\\HtmlSanitizer\\Visitor\\AttributeSanitizer\\MetaRefreshAttributeSanitizer"
          ],
          "packageName": "symfony/html-sanitizer",
          "product": "symfony",
          "repo": "https://github.com/symfony/html-sanitizer",
          "vendor": "sensiolabs",
          "versions": [
            {
              "lessThan": "6.4.50",
              "status": "affected",
              "version": "6.1.0",
              "versionType": "git"
            },
            {
              "lessThan": "7.4.23",
              "status": "affected",
              "version": "7.0.0",
              "versionType": "git"
            },
            {
              "lessThan": "8.1.11",
              "status": "affected",
              "version": "8.0.0",
              "versionType": "git"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.4.50",
                  "versionStartIncluding": "6.1.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.4.23",
                  "versionStartIncluding": "7.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "8.1.11",
                  "versionStartIncluding": "8.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "OR"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Ilia Alshanetsky"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Nicolas Grekas"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cdiv\u003eThe Symfony HtmlSanitizer component\u0026nbsp;\u003ccode\u003eMetaRefreshAttributeSanitizer\u003c/code\u003e\u003cspan\u003e, introduced to fix\u0026nbsp;\u003c/span\u003e\u003cspan\u003eCVE-2026-48761\u003c/span\u003e,\u0026nbsp;\u003cspan\u003es\u003c/span\u003e\u003cspan\u003eanitizes\u0026nbsp;\u003c/span\u003e\u003cspan\u003ethe refresh URL of\u0026nbsp;\u003c/span\u003e\u003ccode\u003econtent\u003c/code\u003e\u003cspan\u003e\u0026nbsp;attributes of\u0026nbsp;\u003c/span\u003e\u003ccode\u003emeta\u003c/code\u003e\u003cspan\u003e\u0026nbsp;tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to\u0026nbsp;\u003c/span\u003e\u003cspan\u003e6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\u003c/span\u003e\u003c/div\u003e\u003cdiv\u003e\u003cspan\u003e\u003cbr\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv\u003eThe shared declarative refresh steps in the WHATWG HTML Standard\u0026nbsp;require a broader approach: the separator after the time may be ASCII whitespace alone, with no\u0026nbsp;\u003ccode\u003e;\u003c/code\u003e\u0026nbsp;or\u0026nbsp;\u003ccode\u003e,\u003c/code\u003e, and the\u0026nbsp;\u003ccode\u003eurl=\u003c/code\u003e\u0026nbsp;keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips\u0026nbsp;\u003ccode\u003eUrlSanitizer\u003c/code\u003e\u0026nbsp;entirely and both\u0026nbsp;\u003ccode\u003eallowLinkSchemes\u003c/code\u003e\u0026nbsp;and\u0026nbsp;\u003ccode\u003eallowLinkHosts\u003c/code\u003e\u0026nbsp;are defeated for the refresh navigation.\u003c/div\u003e\u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\u003cdiv\u003eThis is reachable under any configuration that allows\u0026nbsp;\u003ccode\u003emeta\u003c/code\u003e\u0026nbsp;with\u0026nbsp;\u003ccode\u003ehttp-equiv\u003c/code\u003e\u0026nbsp;and\u0026nbsp;\u003ccode\u003econtent\u003c/code\u003e, including the documented\u0026nbsp;\u003ccode\u003eallowStaticElements()\u003c/code\u003e\u0026nbsp;preset.\u003c/div\u003e"
            }
          ],
          "value": "The Symfony HtmlSanitizer component\u00a0MetaRefreshAttributeSanitizer, introduced to fix\u00a0CVE-2026-48761,\u00a0sanitizes\u00a0the refresh URL of\u00a0content\u00a0attributes of\u00a0meta\u00a0tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to\u00a06.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\n\n\n\n\nThe shared declarative refresh steps in the WHATWG HTML Standard\u00a0require a broader approach: the separator after the time may be ASCII whitespace alone, with no\u00a0;\u00a0or\u00a0,, and the\u00a0url=\u00a0keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips\u00a0UrlSanitizer\u00a0entirely and both\u00a0allowLinkSchemes\u00a0and\u00a0allowLinkHosts\u00a0are defeated for the refresh navigation.\n\n\n\n\nThis is reachable under any configuration that allows\u00a0meta\u00a0with\u00a0http-equiv\u00a0and\u00a0content, including the documented\u00a0allowStaticElements()\u00a0preset."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "PASSIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-186",
              "description": "CWE-186 Overly restrictive regular expression",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601 URL redirection to untrusted site (\u0027open redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-04T18:14:54.592Z",
        "orgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
        "shortName": "Checkmarx"
      },
      "references": [
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://github.com/symfony/symfony/security/advisories/GHSA-wm2w-4mgj-vw33"
        },
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/symfony/symfony/commit/2d4c4fe36200858b91132a95076fff3d9de89d26"
        }
      ],
      "source": {
        "advisory": "GHSA-wm2w-4mgj-vw33",
        "discovery": "UNKNOWN"
      },
      "title": "Symfony: HtmlSanitizer MetaRefreshAttributeSanitizer Matches Only a Narrow Subset of the Browser Refresh Grammar (Incomplete Fix for CVE-2026-48761)",
      "x_generator": {
        "engine": "Vulnogram 1.0.5"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
    "assignerShortName": "Checkmarx",
    "cveId": "CVE-2026-121373",
    "datePublished": "2026-11-04T12:59:22.585Z",
    "dateReserved": "2026-11-03T11:38:38.187Z",
    "dateUpdated": "2026-11-04T18:20:22.620Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-121373",
      "date": "2026-11-10",
      "epss": "0.00482",
      "percentile": "0.41918"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "collectionURL": "https://packagist.org/packages/symfony/html-sanitizer",
                "defaultStatus": "unaffected",
                "modules": [
                  "Symfony\\Component\\HtmlSanitizer\\Visitor\\AttributeSanitizer\\MetaRefreshAttributeSanitizer"
                ],
                "packageName": "symfony/html-sanitizer",
                "product": "symfony",
                "repo": "https://github.com/symfony/html-sanitizer",
                "vendor": "sensiolabs",
                "versions": [
                  {
                    "lessThan": "6.4.50",
                    "status": "affected",
                    "version": "6.1.0",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "7.4.23",
                    "status": "affected",
                    "version": "7.0.0",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "8.1.11",
                    "status": "affected",
                    "version": "8.0.0",
                    "versionType": "git"
                  }
                ]
              }
            ],
            "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "The Symfony HtmlSanitizer component\u00a0MetaRefreshAttributeSanitizer, introduced to fix\u00a0CVE-2026-48761,\u00a0sanitizes\u00a0the refresh URL of\u00a0content\u00a0attributes of\u00a0meta\u00a0tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to\u00a06.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\n\n\n\n\nThe shared declarative refresh steps in the WHATWG HTML Standard\u00a0require a broader approach: the separator after the time may be ASCII whitespace alone, with no\u00a0;\u00a0or\u00a0,, and the\u00a0url=\u00a0keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips\u00a0UrlSanitizer\u00a0entirely and both\u00a0allowLinkSchemes\u00a0and\u00a0allowLinkHosts\u00a0are defeated for the refresh navigation.\n\n\n\n\nThis is reachable under any configuration that allows\u00a0meta\u00a0with\u00a0http-equiv\u00a0and\u00a0content, including the documented\u00a0allowStaticElements()\u00a0preset."
          }
        ],
        "id": "CVE-2026-121373",
        "lastModified": "2026-11-06T21:40:43.450",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "LOW",
                "subIntegrityImpact": "LOW",
                "userInteraction": "PASSIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-121373",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-11-04T17:49:00.814730Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-11-04T13:17:27.350",
        "references": [
          {
            "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
            "url": "https://github.com/symfony/symfony/commit/2d4c4fe36200858b91132a95076fff3d9de89d26"
          },
          {
            "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
            "url": "https://github.com/symfony/symfony/security/advisories/GHSA-wm2w-4mgj-vw33"
          }
        ],
        "sourceIdentifier": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
        "vulnStatus": "Awaiting Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-186"
              },
              {
                "lang": "en",
                "value": "CWE-601"
              }
            ],
            "source": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
            "type": "Secondary"
          }
        ]
      }
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-121373",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-11-04T17:49:00.814730Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-11-04T18:12:17.662Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "collectionURL": "https://packagist.org/packages/symfony/html-sanitizer",
              "defaultStatus": "unaffected",
              "modules": [
                "Symfony\\Component\\HtmlSanitizer\\Visitor\\AttributeSanitizer\\MetaRefreshAttributeSanitizer"
              ],
              "packageName": "symfony/html-sanitizer",
              "product": "symfony",
              "repo": "https://github.com/symfony/html-sanitizer",
              "vendor": "sensiolabs",
              "versions": [
                {
                  "lessThan": "6.4.50",
                  "status": "affected",
                  "version": "6.1.0",
                  "versionType": "git"
                },
                {
                  "lessThan": "7.4.23",
                  "status": "affected",
                  "version": "7.0.0",
                  "versionType": "git"
                },
                {
                  "lessThan": "8.1.11",
                  "status": "affected",
                  "version": "8.0.0",
                  "versionType": "git"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "6.4.50",
                      "versionStartIncluding": "6.1.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "7.4.23",
                      "versionStartIncluding": "7.0.0",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "8.1.11",
                      "versionStartIncluding": "8.0.0",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ],
              "operator": "OR"
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "reporter",
              "value": "Ilia Alshanetsky"
            },
            {
              "lang": "en",
              "type": "remediation developer",
              "value": "Nicolas Grekas"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cdiv\u003eThe Symfony HtmlSanitizer component\u0026nbsp;\u003ccode\u003eMetaRefreshAttributeSanitizer\u003c/code\u003e\u003cspan\u003e, introduced to fix\u0026nbsp;\u003c/span\u003e\u003cspan\u003eCVE-2026-48761\u003c/span\u003e,\u0026nbsp;\u003cspan\u003es\u003c/span\u003e\u003cspan\u003eanitizes\u0026nbsp;\u003c/span\u003e\u003cspan\u003ethe refresh URL of\u0026nbsp;\u003c/span\u003e\u003ccode\u003econtent\u003c/code\u003e\u003cspan\u003e\u0026nbsp;attributes of\u0026nbsp;\u003c/span\u003e\u003ccode\u003emeta\u003c/code\u003e\u003cspan\u003e\u0026nbsp;tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to\u0026nbsp;\u003c/span\u003e\u003cspan\u003e6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\u003c/span\u003e\u003c/div\u003e\u003cdiv\u003e\u003cspan\u003e\u003cbr\u003e\u003c/span\u003e\u003c/div\u003e\u003cdiv\u003eThe shared declarative refresh steps in the WHATWG HTML Standard\u0026nbsp;require a broader approach: the separator after the time may be ASCII whitespace alone, with no\u0026nbsp;\u003ccode\u003e;\u003c/code\u003e\u0026nbsp;or\u0026nbsp;\u003ccode\u003e,\u003c/code\u003e, and the\u0026nbsp;\u003ccode\u003eurl=\u003c/code\u003e\u0026nbsp;keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips\u0026nbsp;\u003ccode\u003eUrlSanitizer\u003c/code\u003e\u0026nbsp;entirely and both\u0026nbsp;\u003ccode\u003eallowLinkSchemes\u003c/code\u003e\u0026nbsp;and\u0026nbsp;\u003ccode\u003eallowLinkHosts\u003c/code\u003e\u0026nbsp;are defeated for the refresh navigation.\u003c/div\u003e\u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\u003cdiv\u003eThis is reachable under any configuration that allows\u0026nbsp;\u003ccode\u003emeta\u003c/code\u003e\u0026nbsp;with\u0026nbsp;\u003ccode\u003ehttp-equiv\u003c/code\u003e\u0026nbsp;and\u0026nbsp;\u003ccode\u003econtent\u003c/code\u003e, including the documented\u0026nbsp;\u003ccode\u003eallowStaticElements()\u003c/code\u003e\u0026nbsp;preset.\u003c/div\u003e"
                }
              ],
              "value": "The Symfony HtmlSanitizer component\u00a0MetaRefreshAttributeSanitizer, introduced to fix\u00a0CVE-2026-48761,\u00a0sanitizes\u00a0the refresh URL of\u00a0content\u00a0attributes of\u00a0meta\u00a0tags using a regular expression that is too narrow, allowing sanitization to be bypassed, and resulting in potential URL redirection to untrusted sites in Symfony versions 6.1.x prior to\u00a06.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.\n\n\n\n\nThe shared declarative refresh steps in the WHATWG HTML Standard\u00a0require a broader approach: the separator after the time may be ASCII whitespace alone, with no\u00a0;\u00a0or\u00a0,, and the\u00a0url=\u00a0keyword is optional. Directives the browser honours, but the regular expression misses are returned unchanged, so the attacker URL skips\u00a0UrlSanitizer\u00a0entirely and both\u00a0allowLinkSchemes\u00a0and\u00a0allowLinkHosts\u00a0are defeated for the refresh navigation.\n\n\n\n\nThis is reachable under any configuration that allows\u00a0meta\u00a0with\u00a0http-equiv\u00a0and\u00a0content, including the documented\u00a0allowStaticElements()\u00a0preset."
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "Automatable": "NOT_DEFINED",
                "Recovery": "NOT_DEFINED",
                "Safety": "NOT_DEFINED",
                "attackComplexity": "LOW",
                "attackRequirements": "NONE",
                "attackVector": "NETWORK",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "exploitMaturity": "NOT_DEFINED",
                "privilegesRequired": "NONE",
                "providerUrgency": "NOT_DEFINED",
                "subAvailabilityImpact": "NONE",
                "subConfidentialityImpact": "LOW",
                "subIntegrityImpact": "LOW",
                "userInteraction": "PASSIVE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
                "version": "4.0",
                "vulnAvailabilityImpact": "NONE",
                "vulnConfidentialityImpact": "NONE",
                "vulnIntegrityImpact": "NONE",
                "vulnerabilityResponseEffort": "NOT_DEFINED"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-186",
                  "description": "CWE-186 Overly restrictive regular expression",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            },
            {
              "descriptions": [
                {
                  "cweId": "CWE-601",
                  "description": "CWE-601 URL redirection to untrusted site (\u0027open redirect\u0027)",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-11-04T18:14:54.592Z",
            "orgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
            "shortName": "Checkmarx"
          },
          "references": [
            {
              "tags": [
                "third-party-advisory"
              ],
              "url": "https://github.com/symfony/symfony/security/advisories/GHSA-wm2w-4mgj-vw33"
            },
            {
              "tags": [
                "patch"
              ],
              "url": "https://github.com/symfony/symfony/commit/2d4c4fe36200858b91132a95076fff3d9de89d26"
            }
          ],
          "source": {
            "advisory": "GHSA-wm2w-4mgj-vw33",
            "discovery": "UNKNOWN"
          },
          "title": "Symfony: HtmlSanitizer MetaRefreshAttributeSanitizer Matches Only a Narrow Subset of the Browser Refresh Grammar (Incomplete Fix for CVE-2026-48761)",
          "x_generator": {
            "engine": "Vulnogram 1.0.5"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "596c5446-0ce5-4ba2-aa66-48b3b757a647",
        "assignerShortName": "Checkmarx",
        "cveId": "CVE-2026-121373",
        "datePublished": "2026-11-04T12:59:22.585Z",
        "dateReserved": "2026-11-03T11:38:38.187Z",
        "dateUpdated": "2026-11-04T18:20:22.620Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON
How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.