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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-42791 Detail

Description

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  EEF
CVSS-B 6.3 MEDIUM
Vector:  CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cna.erlef.org/cves/CVE-2026-42791.html EEF
https://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b EEF
https://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76 EEF
https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff EEF
https://osv.dev/vulnerability/EEF-CVE-2026-42791 EEF
https://www.erlang.org/doc/system/versions.html#order-of-versions EEF

Weakness Enumeration

CWE-ID CWE Name Source
CWE-295 Improper Certificate Validation EEF  
CWE-672 Operation on a Resource after Expiration or Release EEF  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-42791
NVD Published Date:
05/27/2026
NVD Last Modified:
05/27/2026
Source:
EEF