CVE-2026-40477

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.1 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit probability: 0.9%, top 45% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m, epss
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

Thymeleaf is a server-side Java template engine for web and standalone environments. Versions 3.1.3.RELEASE and prior contain a security bypass vulnerability in the expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly restrict the scope of accessible objects, allowing specific potentially sensitive objects to be reached from within a template. If an application developer passes unvalidated user input directly to the template engine, an unauthenticated remote attacker can bypass the library's protections to achieve Server-Side Template Injection (SSTI). This issue has ben fixed in version 3.1.4.RELEASE.

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
41(Track)
EG Risk 41/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
57%
KEV
Not listed

Published

April 17, 2026

Last Modified

August 17, 2026

Advisory Details (1)

Auto-updated Sep 16, 2026
Patch available. Sources: github.
github Patch Available

Improper restriction of the scope of accessible objects in Thymeleaf expressions · Advisory · thymeleaf/thymeleaf · GitHub

https://github.com/thymeleaf/thymeleaf/security/advisories/GHSA-r4v4-5mwr-2fwr

Vendor Advisories for CVE-2026-40477(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatdevspaces/pluginregistry-rhel9:17793594232026-05-28redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 1 ecosystem)
Maven(3)
PackageVulnerable rangeFixed inDependents
org.thymeleaf:thymeleaf1.0.0 ... m1 (81 versions)3.1.4.RELEASE—
org.thymeleaf:thymeleaf-spring53.0.10.RELEASE ... 3.1.3.RELEASE (22 versions)3.1.4.RELEASE—
org.thymeleaf:thymeleaf-spring63.1.0.M1 ... 3.1.3.RELEASE (9 versions)3.1.4.RELEASE—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 256 total refreshes for this CVE.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-17 19:30 UTCEPSS rescore
  4. 2026-09-16 14:08 UTCEPSS rescore
  5. 2026-09-16 05:15 UTCEPSS rescore
  6. 2026-09-15 03:11 UTCEPSS rescore
  7. 2026-09-13 16:47 UTCEPSS rescore
  8. 2026-09-12 15:01 UTCEPSS rescore
  9. 2026-09-11 14:53 UTCEPSS rescore
  10. 2026-09-11 09:37 UTCEPSS rescore
  11. 2026-09-10 09:34 UTCEPSS rescore
  12. 2026-09-08 22:00 UTCEPSS rescore
  13. 2026-09-07 16:01 UTCEPSS rescore
  14. 2026-09-06 13:47 UTCEPSS rescore
  15. 2026-09-04 05:06 UTCEPSS rescore
  16. 2026-09-03 22:46 UTCOSV refresh
  17. 2026-09-02 14:12 UTCEPSS rescore
  18. 2026-09-01 13:53 UTCEPSS rescore
  19. 2026-09-01 04:39 UTCEPSS rescore
  20. 2026-08-30 19:17 UTCEPSS rescore
  21. 2026-08-30 01:22 UTCEPSS rescore
  22. 2026-08-28 21:41 UTCEPSS rescore
  23. 2026-08-27 14:25 UTCEPSS rescore
  24. 2026-08-26 14:46 UTCEPSS rescore
  25. 2026-08-25 13:49 UTCEPSS rescore
Show 75 more
  1. 2026-08-23 00:19 UTCEPSS rescore
  2. 2026-08-21 23:49 UTCEPSS rescore
  3. 2026-08-20 22:55 UTCEPSS rescore
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-18 13:48 UTCEPSS rescore
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-17 12:12 UTCEG score recompute▲ 0.10
  8. 2026-08-17 12:12 UTCVendor advisory
  9. 2026-08-17 12:11 UTCMITRE cvelistV5CVSS v3 → 9.1
  10. 2026-08-16 14:56 UTCEPSS rescore
  11. 2026-08-16 10:28 UTCVendor advisory
  12. 2026-08-16 06:29 UTCEG score recompute
  13. 2026-08-16 06:29 UTCVendor advisory
  14. 2026-08-16 02:14 UTCEPSS rescore
  15. 2026-08-15 02:26 UTCEG score recompute
  16. 2026-08-15 02:26 UTCVendor advisory
  17. 2026-08-15 01:30 UTCEPSS rescore
  18. 2026-08-14 22:20 UTCVendor advisory
  19. 2026-08-14 18:07 UTCVendor advisory
  20. 2026-08-14 12:34 UTCVendor advisory
  21. 2026-08-14 08:35 UTCVendor advisory
  22. 2026-08-14 04:36 UTCEG score recompute
  23. 2026-08-14 04:36 UTCVendor advisory
  24. 2026-08-13 22:00 UTCEPSS rescore
  25. 2026-08-13 08:51 UTCVendor advisory
  26. 2026-08-13 02:44 UTCVendor advisory
  27. 2026-08-12 22:46 UTCVendor advisory
  28. 2026-08-12 18:47 UTCEG score recompute
  29. 2026-08-12 18:47 UTCVendor advisory
  30. 2026-08-12 13:51 UTCEPSS rescore
  31. 2026-08-12 00:54 UTCVendor advisory
  32. 2026-08-11 20:55 UTCVendor advisory
  33. 2026-08-11 16:57 UTCEG score recompute
  34. 2026-08-11 16:57 UTCVendor advisory
  35. 2026-08-11 13:43 UTCEPSS rescore
  36. 2026-08-11 06:32 UTCVendor advisory
  37. 2026-08-11 02:33 UTCEG score recompute
  38. 2026-08-11 02:33 UTCVendor advisory
  39. 2026-08-11 00:00 UTCEPSS rescore
  40. 2026-08-10 12:50 UTCVendor advisory
  41. 2026-08-10 08:38 UTCVendor advisory
  42. 2026-08-10 04:40 UTCVendor advisory
  43. 2026-08-10 00:41 UTCVendor advisory
  44. 2026-08-09 20:42 UTCVendor advisory
  45. 2026-08-09 16:43 UTCEG score recompute
  46. 2026-08-09 16:43 UTCVendor advisory
  47. 2026-08-09 13:46 UTCEPSS rescore
  48. 2026-08-09 12:44 UTCVendor advisory
  49. 2026-08-09 07:51 UTCVendor advisory
  50. 2026-08-09 03:52 UTCEG score recompute
  51. 2026-08-09 03:52 UTCVendor advisory
  52. 2026-08-08 16:37 UTCEPSS rescore
  53. 2026-08-08 09:14 UTCVendor advisory
  54. 2026-08-08 05:15 UTCVendor advisory
  55. 2026-08-08 01:16 UTCVendor advisory
  56. 2026-08-07 21:17 UTCVendor advisory
  57. 2026-08-07 17:17 UTCEG score recompute
  58. 2026-08-07 17:17 UTCVendor advisory
  59. 2026-08-07 13:19 UTCVendor advisory
  60. 2026-08-06 21:29 UTCVendor advisory
  61. 2026-08-06 17:28 UTCEG score recompute
  62. 2026-08-06 17:28 UTCVendor advisory
  63. 2026-08-06 13:46 UTCEPSS rescore
  64. 2026-08-06 11:59 UTCVendor advisory
  65. 2026-08-06 07:15 UTCVendor advisory
  66. 2026-08-06 03:16 UTCVendor advisory
  67. 2026-08-05 23:18 UTCEG score recompute
  68. 2026-08-05 23:18 UTCVendor advisory
  69. 2026-08-05 19:17 UTCEPSS rescore
  70. 2026-08-04 15:10 UTCEPSS rescore
  71. 2026-08-04 13:27 UTCEG score recompute▼ 0.10
  72. 2026-08-04 13:27 UTCVendor advisory
  73. 2026-08-04 13:26 UTCNVD updateCVSS v3 → 9
  74. 2026-08-04 12:34 UTCEG score recompute▲ 0.10
  75. 2026-08-04 12:34 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-40477?
CVE-2026-40477 is a critical vulnerability published on April 17, 2026. Thymeleaf is a server-side Java template engine for web and standalone environments. Versions 3.1.3.RELEASE and prior contain a security bypass vulnerability in the expression execution mechanisms. Although the library provides mechanisms to prevent expression injection, it fails to properly…
When was CVE-2026-40477 disclosed?
CVE-2026-40477 was first published in the National Vulnerability Database on April 17, 2026, with the most recent update on August 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40477 actively exploited?
CVE-2026-40477 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 43.4% of all scored CVEs.
What is the CVSS score of CVE-2026-40477?
CVE-2026-40477 has a CVSS v4.0 base score of 9.1 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-40477?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40477, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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