CVE-2026-42791

LOWNVD 3.73.7—
EchelonGraph scoreMEDIUM confidence

This low-severity CVE scores 3.7 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 77% 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, nvd
3.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 3.7Exploit: NoneExposed: 0

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

Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.

OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid.

This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.

This issue affects OTP from OTP 27.0 before OTP 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.16 before 1.17.1.3, 1.20.3.1, and 1.21.1.

CVSS v3
3.7
EG Score
3.7(medium)
EPSS
23.6%
KEV
Not listed

Published

May 27, 2026

Last Modified

June 2, 2026

References (6)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 39× 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. 2026-07-15 16:57 UTCEPSS rescore
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  3. 2026-07-13 22:30 UTCEPSS rescore
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  8. 2026-07-09 00:18 UTCEG score recompute
  9. 2026-07-08 15:16 UTCEPSS rescore
  10. 2026-07-06 16:27 UTCEPSS rescore
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  18. 2026-06-30 23:22 UTCEPSS rescore
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  20. 2026-06-28 14:07 UTCEPSS rescore
  21. 2026-06-28 07:26 UTCEG score recompute
  22. 2026-06-28 04:56 UTCEPSS rescore
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  24. 2026-06-25 13:49 UTCEPSS rescore
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  1. 2026-06-25 01:33 UTCEG score recompute
  2. 2026-06-24 14:05 UTCEPSS rescore
  3. 2026-06-23 21:33 UTCEPSS rescore
  4. 2026-06-22 14:25 UTCEPSS rescore
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  6. 2026-06-21 14:56 UTCEPSS rescore
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  8. 2026-06-21 01:59 UTCEPSS rescore
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  14. 2026-06-16 01:26 UTCEG score recompute
  15. 2026-06-15 17:49 UTCEPSS rescore
  16. 2026-06-13 23:00 UTCEPSS rescore
  17. 2026-06-12 23:12 UTCEPSS rescore
  18. 2026-06-12 23:12 UTCEPSS rescore
  19. 2026-06-12 19:55 UTCEG score recompute
  20. 2026-06-11 14:00 UTCEPSS rescore
  21. 2026-06-10 22:18 UTCEPSS rescore
  22. 2026-06-10 13:22 UTCEPSS rescore
  23. 2026-06-10 13:22 UTCEPSS rescore
  24. 2026-06-09 14:26 UTCEG score recompute
  25. 2026-06-08 14:17 UTCEPSS rescore
  26. 2026-06-08 14:17 UTCEPSS rescore
  27. 2026-06-07 15:25 UTCEPSS rescore
  28. 2026-06-07 15:25 UTCEPSS rescore
  29. 2026-06-06 13:47 UTCEPSS rescore
  30. 2026-06-06 13:47 UTCEPSS rescore
  31. 2026-06-06 08:56 UTCEG score recompute
  32. 2026-06-05 22:47 UTCEPSS rescore
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  35. 2026-06-04 13:12 UTCEPSS rescore
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  37. 2026-06-03 03:25 UTCEG score recompute▼ 2.60
  38. 2026-06-02 20:13 UTCEPSS rescore
  39. 2026-06-02 02:31 UTCEG score recompute
  40. 2026-06-01 13:52 UTCEPSS rescore
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  42. 2026-06-01 01:37 UTCEG score recompute
  43. 2026-05-31 22:30 UTCEPSS rescore
  44. 2026-05-31 22:30 UTCEPSS rescore
  45. 2026-05-31 00:16 UTCEPSS rescore
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  47. 2026-05-29 13:44 UTCEPSS rescore
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  49. 2026-05-28 13:44 UTCEPSS rescore
  50. 2026-05-28 13:44 UTCEPSS rescore
  51. 2026-05-27 14:13 UTCEG score recompute

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Frequently asked(5)

What is CVE-2026-42791?
CVE-2026-42791 is a low vulnerability published on May 27, 2026. Improper Certificate Validation vulnerability in Erlang OTP publickey (pubkeyocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkeyocsp:verifyresponse/5 and pubkeyocsp:isauthorizedresponder/3 in…
When was CVE-2026-42791 disclosed?
CVE-2026-42791 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on June 2, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42791 actively exploited?
CVE-2026-42791 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 23.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42791?
CVE-2026-42791 has a CVSS v3 base score of 3.7 (NVD).
How do I remediate CVE-2026-42791?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42791, 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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