CVE-2026-6291

MEDIUMNVD 6.56.5—
EchelonGraph scoreMEDIUM confidence

Score 6.5 from GitHub Security Advisory published 2026-06-25. NVD baseline CVSS 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 6.5Exploit: None knownExposed services: Not assessed

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

Bleichenbacher padding oracle in PKCS#7 KTRI decryption. When decrypting PKCS#7 EnvelopedData using RSA PKCS#1 v1.5 key transport, wolfSSL returned distinguishable error codes depending on whether RSA padding validation failed versus whether the decrypted content was malformed. An attacker able to submit crafted EnvelopedData messages and observe error responses could use this as a padding oracle to incrementally recover the encrypted Content Encryption Key (CEK). The fix generates a deterministic pseudo-random fake CEK on padding failure (via HMAC-SHA256) and proceeds with decryption identically, using constant-time operations throughout, so that all failure paths produce the same error regardless of padding validity.

CVSS v3
6.5
EG Score
6.5MEDIUMmedium confidence
EG Risk
34
EG Risk 34/100

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
Severity65% × 45%
Exploitation0% × 40%
Automatability30% × 15%
EPSS PROB
0.2%
EPSS %ILE
14th
KEV
Not listed

Published

June 25, 2026

Last Modified

June 26, 2026

Advisory Details (2)

Auto-updated Jun 25, 2026
No fix on record yet. Sources: github_pr.
genericMentions a patch (unverified)

wolfSSL Security Vulnerabilities | Documentation - wolfSSL

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

PKCS#7 fixes

Fix merged in wolfSSL/wolfssl PR #10203 on 2026-04-24 — awaiting tagged release

https://github.com/wolfSSL/wolfssl/pull/10203

Vendor Advisories for CVE-2026-6291(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 rangeFix by version rangeDependents
wolfssl4.6.0+p1-0+deb11u1 ... 5.9.2-1 (40 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
wolfssl5.5.4-2 ... 5.9.2-1 (27 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
wolfssl5.7.2-0.1 ... 5.9.2-1 (14 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 29× 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 207 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-6291?
CVE-2026-6291 is a medium vulnerability published on June 25, 2026. Bleichenbacher padding oracle in PKCS#7 KTRI decryption. When decrypting PKCS#7 EnvelopedData using RSA PKCS#1 v1.5 key transport, wolfSSL returned distinguishable error codes depending on whether RSA padding validation failed versus whether the decrypted content was malformed. An attacker able to…
When was CVE-2026-6291 disclosed?
CVE-2026-6291 was first published 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-2026-6291 actively exploited?
CVE-2026-6291 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-6291?
CVE-2026-6291 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-6291?
No fix for CVE-2026-6291 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-6291 are linked in the Vendor Advisories panel on this page.

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