Vulnerability-Lookup

CVE-2026-41901 (GCVE-0-2026-41901)

Vulnerability from cvelistv5 – Published: 2026-05-12 22:35 – Updated: 2026-05-13 12:08

Title

Thymeleaf: Improper recognition of unauthorized syntax patterns in sandboxed Thymeleaf expressions

Summary

Thymeleaf is a server-side Java template engine for web and standalone environments. Prior to 3.1.5.RELEASE, a security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf. Although the library provides mechanisms to avoid the execution of potentially dangerous expressions in some specific sandboxed (restricted) contexts, it fails to properly neutralize specific constructs that allow this kind of expressions to be executed. If an application developer passes to the template engine unsanitized variables that contain such expressions, and these values are used in sandboxed contexts inside the templates, these expressions can be executed achieving Server-Side Template Injection (SSTI). This vulnerability is fixed in 3.1.5.RELEASE.

Severity ?

9 (Critical)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

CWE

CWE-917 - Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
CWE-1336 - Improper Neutralization of Special Elements Used in a Template Engine

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/thymeleaf/thymeleaf/security/a…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
thymeleaf	thymeleaf	Affected: < 3.1.5.RELEASE

Show details on NVD website

JSON

To clipboard

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GHSA-C9PH-GXWW-7744

Vulnerability from github – Published: 2026-05-04 21:15 – Updated: 2026-05-13 16:43

Summary

Sandboxed Thymeleaf expressions vulnerable to improper recognition of unauthorized syntax patterns

Details

Impact

A security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 3.1.4.RELEASE. Although the library provides mechanisms to avoid the execution of potentially dangerous expressions in some specific sandboxed (restricted) contexts, it fails to properly neutralize specific constructs that allow this kind of expressions to be executed. If an application developer passes to the template engine unsanitized variables that contain such expressions, and these values are used in sandboxed contexts inside the templates, these expressions can be executed achieving Server-Side Template Injection (SSTI).

Patches

This has been fixed in Thymeleaf 3.1.5.RELEASE. All users are advised to upgrade immediately.

Workarounds

No workaround is available beyond ensuring applications do not pass unvalidated/unsanitized data directly to the template engine. Upgrading to 3.1.5.RELEASE is strongly recommended in any case.

Severity ?

9.0 (Critical)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.4.RELEASE"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.thymeleaf:thymeleaf"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.5.RELEASE"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.4.RELEASE"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.thymeleaf:thymeleaf-spring5"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.5.RELEASE"
            }
          ],
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        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.4.RELEASE"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "org.thymeleaf:thymeleaf-spring6"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.5.RELEASE"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-41901"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1336",
      "CWE-917"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-04T21:15:20Z",
    "nvd_published_at": "2026-05-12T23:16:17Z",
    "severity": "CRITICAL"
  },
  "details": "### Impact\n\nA security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf up to and including 3.1.4.RELEASE. Although the library provides mechanisms to avoid the execution of potentially dangerous expressions in some specific sandboxed (restricted) contexts, it fails to properly neutralize specific constructs that allow this kind of expressions to be executed. If an application developer passes to the template engine unsanitized variables that contain such expressions, and these values are used in sandboxed contexts inside the templates, these expressions can be executed achieving Server-Side Template Injection (SSTI).\n\n### Patches\n\nThis has been fixed in Thymeleaf 3.1.5.RELEASE. All users are advised to upgrade immediately.\n\n### Workarounds\n\nNo workaround is available beyond ensuring applications do not pass unvalidated/unsanitized data directly to the template engine. Upgrading to 3.1.5.RELEASE is strongly recommended in any case.",
  "id": "GHSA-c9ph-gxww-7744",
  "modified": "2026-05-13T16:43:36Z",
  "published": "2026-05-04T21:15:20Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-c9ph-gxww-7744"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-41901"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thymeleaf/thymeleaf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Sandboxed Thymeleaf expressions vulnerable to improper recognition of unauthorized syntax patterns"
}

FKIE_CVE-2026-41901

Vulnerability from fkie_nvd - Published: 2026-05-12 23:16 - Updated: 2026-05-13 16:10

Severity ?

9.0 (Critical) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-c9ph-gxww-7744

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Thymeleaf is a server-side Java template engine for web and standalone environments. Prior to 3.1.5.RELEASE, a security bypass vulnerability exists in the expression execution mechanisms of Thymeleaf. Although the library provides mechanisms to avoid the execution of potentially dangerous expressions in some specific sandboxed (restricted) contexts, it fails to properly neutralize specific constructs that allow this kind of expressions to be executed. If an application developer passes to the template engine unsanitized variables that contain such expressions, and these values are used in sandboxed contexts inside the templates, these expressions can be executed achieving Server-Side Template Injection (SSTI). This vulnerability is fixed in 3.1.5.RELEASE."
    }
  ],
  "id": "CVE-2026-41901",
  "lastModified": "2026-05-13T16:10:57.817",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.0,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H",
          "version": "3.1"
        },
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        "impactScore": 6.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-12T23:16:17.060",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-c9ph-gxww-7744"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-917"
        },
        {
          "lang": "en",
          "value": "CWE-1336"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
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}

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.

Action not permitted

CVE-2026-41901 (GCVE-0-2026-41901)

GHSA-C9PH-GXWW-7744

Impact

Patches

Workarounds

FKIE_CVE-2026-41901

Tags

Sightings

Nomenclature