CVE-2026-40257

MEDIUMPre-NVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 95% 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: epss, secondary
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.21.0 and prior to version 4.11.0, the ARM Crypto Extensions accelerated SHA-3 implementation has an off-by-one error that can cause a massive heap overflow that corrupts all TEE kernel memory following the hash state. This affects all platforms built with CFG_CRYPTO_WITH_CE82=y (ARMv8.2+ with SHA3 Crypto Extensions). Version 4.11.0 contains a patch. As a workaround, disable SHA3 Crypto Extensions with CFG_CRYPTO_WITH_CE82=n.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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
Severity55% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

July 6, 2026

Last Modified

July 7, 2026

Advisory Details (1)

Auto-updated Jul 7, 2026
Patch available. Sources: github.
github Patch Available

SHA-3 accelerated finalize heap overflow · Advisory · OP-TEE/optee_os · GitHub

https://github.com/OP-TEE/optee_os/security/advisories/GHSA-75x4-j8p9-55qv

Affected Packages

(2 across 2 ecosystems)
Debian:13(1)
PackageVulnerable rangeFixed inDependents
optee-os4.10.0-1 ... 4.9.0-1 (6 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
optee-os4.10.0-1 ... 4.9.0-1 (6 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 38× 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.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-11 09:37 UTCEPSS rescore
  3. 2026-09-10 09:34 UTCEPSS rescore
  4. 2026-09-08 22:00 UTCEPSS rescore
  5. 2026-09-07 16:01 UTCEPSS rescore
  6. 2026-09-06 13:47 UTCEPSS rescore
  7. 2026-09-05 23:11 UTCEG score recompute
  8. 2026-09-04 05:06 UTCEPSS rescore
  9. 2026-09-02 14:12 UTCEPSS rescore
  10. 2026-09-01 13:53 UTCEPSS rescore
  11. 2026-08-30 19:17 UTCEPSS rescore
  12. 2026-08-30 08:15 UTCEG score recompute
  13. 2026-08-30 01:22 UTCEPSS rescore
  14. 2026-08-28 21:41 UTCEPSS rescore
  15. 2026-08-27 21:59 UTCEG score recompute
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-26 13:55 UTCEG score recompute
  19. 2026-08-25 13:49 UTCEPSS rescore
  20. 2026-08-25 12:01 UTCEG score recompute
  21. 2026-08-24 10:02 UTCEG score recompute
  22. 2026-08-23 07:05 UTCEG score recompute
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-22 05:48 UTCEG score recompute
  25. 2026-08-21 23:49 UTCEPSS rescore
Show 60 more
  1. 2026-08-21 04:18 UTCEG score recompute
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-20 02:29 UTCEG score recompute
  4. 2026-08-19 17:03 UTCEPSS rescore
  5. 2026-08-17 22:41 UTCEG score recompute
  6. 2026-08-17 13:47 UTCEPSS rescore
  7. 2026-08-16 21:02 UTCEG score recompute
  8. 2026-08-16 14:56 UTCEPSS rescore
  9. 2026-08-16 02:14 UTCEPSS rescore
  10. 2026-08-15 19:45 UTCEG score recompute
  11. 2026-08-15 01:30 UTCEPSS rescore
  12. 2026-08-14 18:28 UTCEG score recompute
  13. 2026-08-13 22:00 UTCEPSS rescore
  14. 2026-08-12 15:47 UTCEG score recompute
  15. 2026-08-12 13:51 UTCEPSS rescore
  16. 2026-08-11 14:30 UTCEG score recompute
  17. 2026-08-11 13:43 UTCEPSS rescore
  18. 2026-08-11 00:00 UTCEPSS rescore
  19. 2026-08-10 13:14 UTCEG score recompute
  20. 2026-08-09 13:46 UTCEPSS rescore
  21. 2026-08-09 11:57 UTCEG score recompute
  22. 2026-08-08 16:37 UTCEPSS rescore
  23. 2026-08-08 10:40 UTCEG score recompute
  24. 2026-08-07 09:22 UTCEG score recompute
  25. 2026-08-06 13:46 UTCEPSS rescore
  26. 2026-08-06 08:05 UTCEG score recompute
  27. 2026-08-05 19:17 UTCEPSS rescore
  28. 2026-08-04 03:10 UTCEG score recompute
  29. 2026-08-03 10:36 UTCEPSS rescore
  30. 2026-08-03 01:54 UTCEG score recompute
  31. 2026-08-02 02:27 UTCEPSS rescore
  32. 2026-08-02 00:37 UTCEG score recompute
  33. 2026-08-01 04:16 UTCEPSS rescore
  34. 2026-07-30 21:57 UTCEG score recompute
  35. 2026-07-30 16:28 UTCEPSS rescore
  36. 2026-07-30 01:30 UTCEPSS rescore
  37. 2026-07-28 17:18 UTCEG score recompute
  38. 2026-07-27 15:46 UTCEG score recompute
  39. 2026-07-27 14:13 UTCEPSS rescore
  40. 2026-07-26 14:54 UTCEPSS rescore
  41. 2026-07-26 14:54 UTCEPSS rescore
  42. 2026-07-26 12:47 UTCEG score recompute
  43. 2026-07-24 14:17 UTCEPSS rescore
  44. 2026-07-24 14:17 UTCEPSS rescore
  45. 2026-07-23 03:11 UTCEG score recompute
  46. 2026-07-22 14:08 UTCEPSS rescore
  47. 2026-07-20 17:08 UTCEPSS rescore
  48. 2026-07-19 14:31 UTCEPSS rescore
  49. 2026-07-18 10:04 UTCEPSS rescore
  50. 2026-07-16 17:03 UTCEPSS rescore
  51. 2026-07-15 16:57 UTCEPSS rescore
  52. 2026-07-15 16:57 UTCEPSS rescore
  53. 2026-07-13 22:30 UTCEPSS rescore
  54. 2026-07-12 05:46 UTCEPSS rescore
  55. 2026-07-11 08:27 UTCEPSS rescore
  56. 2026-07-09 19:10 UTCEPSS rescore
  57. 2026-07-08 15:15 UTCEPSS rescore
  58. 2026-07-07 13:46 UTCEPSS rescore
  59. 2026-07-06 16:43 UTCEG score recompute
  60. 2026-07-06 16:41 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-40257?
CVE-2026-40257 is a medium vulnerability published on July 6, 2026. OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.21.0 and prior to version 4.11.0, the ARM Crypto Extensions accelerated SHA-3 implementation has an off-by-one…
When was CVE-2026-40257 disclosed?
CVE-2026-40257 was first published in the National Vulnerability Database on July 6, 2026, with the most recent update on July 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40257 actively exploited?
CVE-2026-40257 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.3% of all scored CVEs.
What is the CVSS score of CVE-2026-40257?
CVE-2026-40257 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-40257?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40257, 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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