CVE-2026-42791
3.7 LOWImproper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an e...
Published: 2026-05-27 · Last updated: 2026-06-02
Severity and scoring
- CVSS
- 3.7 LOW
- Vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- CWE
- CWE-295, CWE-672
Affected products
| Vendor | Product |
|---|---|
| erlang | erlang\/otp |
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.
Source: NVD
References
- [NVD]https://nvd.nist.gov/vuln/detail/CVE-2026-42791
- [Other]https://cna.erlef.org/cves/CVE-2026-42791.html
- [Patch]https://github.com/erlang/otp/commit/7995f1fdaee3da569bb810358ce0f546471d169b
- [Patch]https://github.com/erlang/otp/commit/b3870e02405c709a872b01ba6086065620cdfe76
- [Vendor advisory]https://github.com/erlang/otp/security/advisories/GHSA-cjxj-wj6x-3fff
- [Other]https://osv.dev/vulnerability/EEF-CVE-2026-42791
- [Other]https://www.erlang.org/doc/system/versions.html#order-of-versions
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