CVE-2026-41901
Thymeleaf: Improper recognition of unauthorized syntax patterns in sandboxed Thymeleaf expressions
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Thymeleaf: Improper recognition of unauthorized syntax patterns in sandboxed Thymeleaf expressions
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.
- Record
CVE-2026-41901- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-917, CWE-1336
- Updated
- 2026-11-02
EUVDEUVD-2026-29872
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.
- Record
EUVD-2026-29872- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-c9ph-gxww-7744
Sandboxed Thymeleaf expressions vulnerable to improper recognition of unauthorized syntax patterns
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.
- Record
GHSA-c9ph-gxww-7744- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-917, CWE-1336
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-41901- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-917, CWE-1336
- Updated
- 2026-11-02
OSV
Thymeleaf: Improper recognition of unauthorized syntax patterns in sandboxed Thymeleaf expressions
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.
- Record
CVE-2026-41901- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-1336, CWE-917
- Updated
- 2026-11-02
OSVGHSA-c9ph-gxww-7744
Sandboxed Thymeleaf expressions vulnerable to improper recognition of unauthorized syntax patterns
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.
- Record
GHSA-c9ph-gxww-7744- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-1336, CWE-917
- Updated
- 2026-11-02
Show 7 moreShow less
OSVRHLW-2026-e0e5640c50ceea84
Lightwell Security Advisory: thymeleaf 3.0.15.RELEASE-rhlw-00009
Red Hat Lightwell has released org.thymeleaf:thymeleaf 3.0.15.RELEASE-rhlw-00009 with backported fixes for CVE-2026-40477, CVE-2026-40478, and CVE-2026-41901.
CVE-2026-40477: Improper restriction of the scope of accessible objects in Thymeleaf expressions
CVE-2026-40478: Improper neutralization of specific syntax patterns for unauthorized expressions in Thymeleaf
CVE-2026-41901: Thymeleaf: Improper recognition of unauthorized syntax patterns in sandboxed Thymeleaf expressions
This patched artifact is a drop-in replacement for org.thymeleaf:thymeleaf 3.0.15.RELEASE-rhlw-00009 from Maven Central.
- Record
RHLW-2026-e0e5640c50ceea84- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-06
OSVCLSA-2026-1784682981 No score
TuxCare security update for org.thymeleaf:thymeleaf (1 CVE)
TuxCare rebuilt org.thymeleaf:thymeleaf to address 1 CVE. Fixed in 3.1.2.RELEASE-tuxcare.1.
- Record
CLSA-2026-1784682981- Updated
- 2026-11-02
OSVCLSA-2026-1784856214 No score
TuxCare security update for org.thymeleaf (1 CVE)
TuxCare rebuilt 3 org.thymeleaf packages to address 1 CVE. Fixed in 3.1.3.RELEASE-tuxcare.1.
- Record
CLSA-2026-1784856214- Updated
- 2026-11-02
OSVCLSA-2026-1788881357 No score
TuxCare security update for org.thymeleaf:thymeleaf (1 CVE)
TuxCare rebuilt org.thymeleaf:thymeleaf to address 1 CVE. Fixed in 3.1.3.RELEASE-tuxcare.2.
- Record
CLSA-2026-1788881357- Updated
- 2026-11-02
OSVCLSA-2026-1788887721 No score
TuxCare security update for org.thymeleaf (1 CVE)
TuxCare rebuilt 2 org.thymeleaf packages to address 1 CVE. Fixed in 3.1.3.RELEASE-tuxcare.2.
- Record
CLSA-2026-1788887721- Updated
- 2026-11-02
OSVCLSA-2026-1789561134 No score
TuxCare security update for org.thymeleaf:thymeleaf (1 CVE)
TuxCare rebuilt org.thymeleaf:thymeleaf to address 1 CVE. Fixed in 3.1.2.RELEASE-tuxcare.2.
- Record
CLSA-2026-1789561134- Updated
- 2026-11-02
OSVCLSA-2026-1789577899 No score
TuxCare security update for org.thymeleaf (1 CVE)
TuxCare rebuilt 2 org.thymeleaf packages to address 1 CVE. Fixed in 3.1.2.RELEASE-tuxcare.2.
- Record
CLSA-2026-1789577899- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.thymeleaf:thymeleafMaven |
through 3.1.4.RELEASE | 3.1.5.RELEASE |
org.thymeleaf:thymeleaf-spring5Maven |
through 3.1.4.RELEASE | 3.1.5.RELEASE |
org.thymeleaf:thymeleaf-spring6Maven |
through 3.1.4.RELEASE | 3.1.5.RELEASE |
org.thymeleaf:thymeleafTuxCare:Maven |
3.1.3.RELEASE up to 3.1.3.RELEASE-tuxcare.2, plus listed versions 3.1.3.RELEASE-tuxcare.1 |
3.1.3.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleaf-spring5TuxCare:Maven |
3.1.3.RELEASE up to 3.1.3.RELEASE-tuxcare.2, plus listed versions 3.1.3.RELEASE-tuxcare.1 |
3.1.3.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleaf-spring6TuxCare:Maven |
3.1.3.RELEASE up to 3.1.3.RELEASE-tuxcare.2, plus listed versions 3.1.3.RELEASE-tuxcare.1 |
3.1.3.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleafTuxCare:Maven |
3.1.2.RELEASE up to 3.1.2.RELEASE-tuxcare.2, plus listed versions 3.1.2.RELEASE-tuxcare.1 |
3.1.2.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleaf-spring5TuxCare:Maven |
3.1.2.RELEASE up to 3.1.2.RELEASE-tuxcare.2, plus listed versions 3.1.2.RELEASE-tuxcare.1 |
3.1.2.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleaf-spring6TuxCare:Maven |
3.1.2.RELEASE up to 3.1.2.RELEASE-tuxcare.2, plus listed versions 3.1.2.RELEASE-tuxcare.1 |
3.1.2.RELEASE-tuxcare.2 |
org.thymeleaf:thymeleafMaven |
before 3.1.5.RELEASE, plus listed versions 1.0.01.0.0-beta11.0.0-beta21.0.0-beta31.0.0-beta4 Show 45 moreShow less1.0.0-beta51.0.11.1.01.1.11.1.21.1.31.1.41.1.52.0.02.0.0-beta12.0.0-beta22.0.12.0.102.0.112.0.122.0.132.0.142.0.152.0.162.0.172.0.182.0.192.0.22.0.202.0.212.0.32.0.42.0.52.0.62.0.72.0.82.0.92.1.0-beta12.1.0-beta22.1.0-m12.1.0-m22.1.0-m32.1.0.RELEASE2.1.1.RELEASE2.1.2.RELEASE2.1.3.RELEASE2.1.4.RELEASE2.1.5.RELEASE2.1.6.RELEASE3.0.0.ALPHA01 |
3.1.5.RELEASE |
org.thymeleaf:thymeleaf-spring5Maven |
before 3.1.5.RELEASE, plus listed versions 3.0.10.RELEASE3.0.11.RELEASE3.0.12.RELEASE3.0.13.RELEASE3.0.14.RELEASE Show 18 moreShow less3.0.15.RELEASE3.0.3.M13.0.4.M23.0.5.M33.0.6.M43.0.7.RC13.0.8.RELEASE3.0.9.RELEASE3.1.0.M13.1.0.M23.1.0.M33.1.0.RC13.1.0.RC23.1.0.RELEASE3.1.1.RELEASE3.1.2.RELEASE3.1.3.RELEASE3.1.4.RELEASE |
3.1.5.RELEASE |
org.thymeleaf:thymeleaf-spring6Maven |
before 3.1.5.RELEASE, plus listed versions 3.1.0.M13.1.0.M23.1.0.M33.1.0.RC13.1.0.RC2 Show 5 moreShow less3.1.0.RELEASE3.1.1.RELEASE3.1.2.RELEASE3.1.3.RELEASE3.1.4.RELEASE |
3.1.5.RELEASE |
org.thymeleaf:thymeleafRed Hat Lightwell:Maven From an advisory covering 3 CVEs |
before 3.0.15.RELEASE-rhlw-00009, plus listed versions 1.0.01.0.0-beta11.0.0-beta21.0.0-beta31.0.0-beta4 Show 45 moreShow less1.0.0-beta51.0.11.1.01.1.11.1.21.1.31.1.41.1.52.0.02.0.0-beta12.0.0-beta22.0.12.0.102.0.112.0.122.0.132.0.142.0.152.0.162.0.172.0.182.0.192.0.22.0.202.0.212.0.32.0.42.0.52.0.62.0.72.0.82.0.92.1.0-beta12.1.0-beta22.1.0-m12.1.0-m22.1.0-m32.1.0.RELEASE2.1.1.RELEASE2.1.2.RELEASE2.1.3.RELEASE2.1.4.RELEASE2.1.5.RELEASE2.1.6.RELEASE3.0.0.ALPHA01 |
3.0.15.RELEASE-rhlw-00009 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | HORKimhab/CVE-2026-41901 | 2026-05-23 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | OSV | |
| affected | ||
| exploitation, facts | ||
| affected | ||
| affected | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-41901 is a critical vulnerability (CVSS 9.0) in Thymeleaf, published May 4, 2026. EUVD reports exploitation since October 10, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in org.thymeleaf:thymeleaf 3.1.5.RELEASE.
References
github.com/thymeleaf/thymeleaf/security/advisories/GHSA-c9ph-gxww-7744
nvd.nist.gov/vuln/detail/CVE-2026-41901
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40477.json
Show 12 moreShow less
access.redhat.com/errata/RHSA-2026:21772
Left out here: 54 versions. The JSON record has them.