CVE-2026-42791
3.7 · LOWOverview
CVE-2026-42791 is a low-severity vulnerability affecting erlang erlang\/otp. It was published on May 27, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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
Remediation
Check the references section for vendor advisories and patches from erlang. Update erlang\/otp to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| erlang | erlang\/otp | >= 27.0, < 27.3.4.12 | Affected |
References
Frequently Asked Questions
What is CVE-2026-42791?
CVE-2026-42791 is a low-severity vulnerability affecting erlang erlang\/otp. It was published on May 27, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
How severe is CVE-2026-42791?
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-42791?
Check the references section for vendor advisories and patches from erlang. Update erlang\/otp to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-42791?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-42791 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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