CVE-2026-5187

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: LOW) published 2026-04-09. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

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

Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers pass sizeof(decOid) (64 bytes on 64-bit platforms) instead of the element count MAX_OID_SZ (32), causing the function to accept crafted OIDs with 33 or more arcs that write past the end of the allocated buffer.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
44(Track)
EG Risk 44/100SSVC: 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
Severity98% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

April 9, 2026

Last Modified

April 16, 2026

Advisory Details (1)

Auto-updated Sep 17, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

GitHub - wolfSSL/wolfssl: The wolfSSL library is a small, fast, portable implementation of TLS/SSL for embedded devices to the cloud. wolfSSL supports up to TLS 1.3 and DTLS 1.3! Update to wolfSSL 5.9.1 for the latest CVE fixes. · GitHub

https://github.com/wolfSSL/wolfssl

Vendor Advisories for CVE-2026-5187(1)

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(2)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 24× 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 226 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-5187?
CVE-2026-5187 is a critical vulnerability published on April 9, 2026. Two potential heap out-of-bounds write locations existed in DecodeObjectId() in wolfcrypt/src/asn.c. First, a bounds check only validates one available slot before writing two OID arc values (out[0] and out[1]), enabling a 2-byte out-of-bounds write when outSz equals 1. Second, multiple callers…
When was CVE-2026-5187 disclosed?
CVE-2026-5187 was first published in the National Vulnerability Database on April 9, 2026, with the most recent update on April 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-5187 actively exploited?
CVE-2026-5187 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 78.9% of all scored CVEs.
What is the CVSS score of CVE-2026-5187?
CVE-2026-5187 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-5187?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-5187, 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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