FKIE_CVE-2026-55599

Vulnerability from fkie_nvd - Published: 2026-06-22 21:16 - Updated: 2026-06-26 20:10
Severity
5.8 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Summary
phpseclib is a PHP secure communications library. From 0.1.1 until 1.0.30, 2.0.55, and 3.0.54, when an application validates an untrusted X.509 certificate with phpseclib, X509::validateSignature() reads a URL out of that certificate's Authority Information Access (AIA) extension and connects to it. Attacker who supplies certificate fully controls host, port, and path of that connection. URL fetching is enabled by default, and no destination is blocked. An unauthenticated attacker can therefore make a validating server open connections to internal hosts and ports it should never reach, for example loopback 127.0.0.1, cloud metadata address 169.254.169.254, and internal-only services. This is a server-side request forgery (SSRF) caused by an insecure default. This vulnerability is fixed in 1.0.30, 2.0.55, and 3.0.54.
References
security-advisories@github.comhttps://github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4Exploit, Mitigation, Vendor Advisory
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4Exploit, Mitigation, Vendor Advisory
Impacted products
Vendor Product Version
phpseclib phpseclib *
phpseclib phpseclib *
phpseclib phpseclib *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "phpseclib",
          "vendor": "phpseclib",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.1.1, \u003c 1.0.30"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.0.0, \u003c 2.0.55"
            },
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.0.54"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "904AD9BC-EED0-43F3-80F9-C4617CA0D15F",
              "versionEndExcluding": "1.0.30",
              "versionStartIncluding": "0.1.1",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "5BEE9570-5BD0-4C69-B435-B8CB4EFFB05A",
              "versionEndExcluding": "2.0.55",
              "versionStartIncluding": "2.0.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:phpseclib:phpseclib:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "97CEDD42-244C-42D8-8BCC-AB611550E504",
              "versionEndExcluding": "3.0.54",
              "versionStartIncluding": "3.0.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "phpseclib is a PHP secure communications library. From 0.1.1 until 1.0.30, 2.0.55, and 3.0.54, when an application validates an untrusted X.509 certificate with phpseclib, X509::validateSignature() reads a URL out of that certificate\u0027s Authority Information Access (AIA) extension and connects to it. Attacker who supplies certificate fully controls host, port, and path of that connection. URL fetching is enabled by default, and no destination is blocked. An unauthenticated attacker can therefore make a validating server open connections to internal hosts and ports it should never reach, for example loopback 127.0.0.1, cloud metadata address 169.254.169.254, and internal-only services. This is a server-side request forgery (SSRF) caused by an insecure default. This vulnerability is fixed in 1.0.30, 2.0.55, and 3.0.54."
    }
  ],
  "id": "CVE-2026-55599",
  "lastModified": "2026-06-26T20:10:05.340",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.8,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55599",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-23T14:12:41.401298Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-22T21:16:25.903",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-918"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}


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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.


Detection rules are retrieved from Rulezet.