CVE-2026-6291

MEDIUMNVD 6.56.5—
EchelonGraph scoreHIGH 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
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0

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

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
6.5(high)
EG Risk
—
EPSS
4.9%
KEV
Not listed

Published

June 25, 2026

Last Modified

June 26, 2026

Advisory Details (2)

Auto-updated Jun 25, 2026
Patch available. Sources: github_pr.
generic Patch Available

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.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 67× 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. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:25 UTCEPSS rescore
  4. 2026-07-21 15:25 UTCEPSS rescore
  5. 2026-07-20 17:08 UTCEPSS rescore
  6. 2026-07-19 14:31 UTCEPSS rescore
  7. 2026-07-19 02:29 UTCEPSS rescore
  8. 2026-07-18 10:04 UTCEPSS rescore
  9. 2026-07-16 18:42 UTCGHSA enrichment
  10. 2026-07-16 17:03 UTCEPSS rescore
  11. 2026-07-15 20:40 UTCGHSA enrichment
  12. 2026-07-15 16:57 UTCEPSS rescore
  13. 2026-07-15 02:00 UTCEPSS rescore
  14. 2026-07-15 02:00 UTCEPSS rescore
  15. 2026-07-14 22:52 UTCGHSA enrichment
  16. 2026-07-14 01:07 UTCGHSA enrichment
  17. 2026-07-13 22:31 UTCEPSS rescore
  18. 2026-07-13 06:13 UTCEPSS rescore
  19. 2026-07-13 06:13 UTCEPSS rescore
  20. 2026-07-13 03:20 UTCGHSA enrichment
  21. 2026-07-12 05:33 UTCGHSA enrichment
  22. 2026-07-11 08:27 UTCEPSS rescore
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-11 07:47 UTCGHSA enrichment
  25. 2026-07-10 10:01 UTCGHSA enrichment
Show 42 more
  1. 2026-07-09 19:10 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-09 12:14 UTCGHSA enrichment
  4. 2026-07-08 15:16 UTCEPSS rescore
  5. 2026-07-08 15:16 UTCEPSS rescore
  6. 2026-07-08 14:27 UTCGHSA enrichment
  7. 2026-07-07 16:39 UTCGHSA enrichment
  8. 2026-07-07 13:46 UTCEPSS rescore
  9. 2026-07-07 13:46 UTCEPSS rescore
  10. 2026-07-06 17:07 UTCGHSA enrichment
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 02:23 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-05 19:19 UTCGHSA enrichment
  16. 2026-07-05 02:31 UTCEPSS rescore
  17. 2026-07-05 02:30 UTCEPSS rescore
  18. 2026-07-04 21:33 UTCGHSA enrichment
  19. 2026-07-04 06:31 UTCEPSS rescore
  20. 2026-07-04 06:31 UTCEPSS rescore
  21. 2026-07-03 23:46 UTCGHSA enrichment
  22. 2026-07-03 02:01 UTCGHSA enrichment
  23. 2026-07-02 04:14 UTCGHSA enrichment
  24. 2026-07-01 15:07 UTCEPSS rescore
  25. 2026-07-01 06:27 UTCGHSA enrichment
  26. 2026-06-30 23:22 UTCEPSS rescore
  27. 2026-06-30 08:41 UTCGHSA enrichment
  28. 2026-06-29 14:06 UTCEPSS rescore
  29. 2026-06-29 10:55 UTCGHSA enrichment
  30. 2026-06-28 14:07 UTCEPSS rescore
  31. 2026-06-28 13:08 UTCGHSA enrichment
  32. 2026-06-28 04:56 UTCEPSS rescore
  33. 2026-06-27 15:22 UTCEG score recompute▲ 0.50
  34. 2026-06-27 15:22 UTCGHSA enrichment
  35. 2026-06-27 03:08 UTCEPSS rescore
  36. 2026-06-26 17:41 UTCNVD updateCVSS v3 → 6.5
  37. 2026-06-26 17:36 UTCGHSA enrichment
  38. 2026-06-25 19:50 UTCEG score recompute▲ 6.00
  39. 2026-06-25 19:50 UTCGHSA enrichment
  40. 2026-06-25 19:49 UTCNVD updateCVSS v3 → 6 · CVSS v4 → 6
  41. 2026-06-25 18:46 UTCEG score recompute
  42. 2026-06-25 18:46 UTCGHSA enrichment

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 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-2026-6291 actively exploited?
CVE-2026-6291 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
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?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-6291, 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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