CVE-2026-12340

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory published 2026-06-25. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

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

Out-of-bounds heap read during SM2/SM3 certificate signature verification. When parsing a certificate with an SM3wSM2 signature, the Subject Key Identifier computation reads the trailing 65 bytes of the public key without checking that the key is at least that long. A public key shorter than 65 bytes results in an out-of-bounds heap read, leading to a potential crash (denial of service); there is no out-of-bounds write. Note this only affects builds with SM2 support (--enable-sm2 or --enable-all).

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
22%
KEV
Not listed

Published

June 25, 2026

Last Modified

June 26, 2026

Advisory Details (2)

Auto-updated Jun 26, 2026
Patch available. Sources: github_pr.
generic Patch Available

wolfSSL Security Vulnerabilities | Documentation - wolfSSL

https://www.wolfssl.com/docs/security-vulnerabilities/
github_pr

Fixes for SM2/3 and FindMultiAttrib

Fix merged in wolfSSL/wolfssl PR #10641 on 2026-06-10 — awaiting tagged release

https://github.com/wolfSSL/wolfssl/pull/10641

Vendor Advisories for CVE-2026-12340(2)

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

Affected Packages

(3 across 3 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
wolfssl4.6.0+p1-0+deb11u1 ... 5.9.2-1 (40 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
wolfssl5.5.4-2 ... 5.9.2-1 (27 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
wolfssl5.7.2-0.1 ... 5.9.2-1 (14 versions)——

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 56× 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 202 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-12340?
CVE-2026-12340 is a high vulnerability published on June 25, 2026. Out-of-bounds heap read during SM2/SM3 certificate signature verification. When parsing a certificate with an SM3wSM2 signature, the Subject Key Identifier computation reads the trailing 65 bytes of the public key without checking that the key is at least that long. A public key shorter than 65…
When was CVE-2026-12340 disclosed?
CVE-2026-12340 was first published in the National Vulnerability Database on June 25, 2026, with the most recent update on June 26, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-12340 actively exploited?
CVE-2026-12340 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 77.8% of all scored CVEs.
What is the CVSS score of CVE-2026-12340?
CVE-2026-12340 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-12340?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-12340, 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.

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