Allocation of resources without limits in Erlang/OTP publickey certificate path validation allows a remote unauthenticated attacker to cause denial of service by sending a crafted X.509 certificate chain during the TLS handshake.

During RFC 5280 policy processing in publickey:pkixpathvalidation/3, the certificate policy tree maintained by pubkeypolicytree grows without an upper bound. When a certificate chain contains M policies per certificate and K certificates, the tree grows on the order of M^K nodes because pubkeypolicytree:addleaves/2 and pubkeypolicytree:addleafsiblings/2 extend the tree per policy per certificate. A modest chain with many policies per certificate is enough to pin BEAM schedulers and exhaust the node's memory, taking down the entire VM. The attacker only needs to be able to present a certificate chain to the victim, which is the normal precondition for a TLS handshake, so exploitation succeeds against any incoming or outgoing TLS connection that validates the peer's chain (the default for SSL/TLS clients and mutual-TLS servers).

This is the same vulnerability class as OpenSSL's X509verifycert policy tree DoS.

This vulnerability is associated with program files lib/publickey/src/pubkeypolicytree.erl and program routines pubkeypolicytree:addleaves/2 and pubkeypolicytree:addleafsiblings/2.

This issue affects OTP from OTP 26.2 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to publickey from 1.15 before 1.21.4, 1.20.3.4 and 1.17.1.5.

Improper Certificate Validation vulnerability in Erlang OTP publickey (pubkeyocsp module) allows OCSP designated-responder authorization bypass via missing signature verification.

The OCSP response validation in publickey:pkixocspvalidate/5 does not verify that a CA-designated responder certificate was cryptographically signed by the issuing CA. Instead, it only checks that the responder certificate's issuer name matches the CA's subject name and that the certificate has the OCSPSigning extended key usage. An attacker who can intercept or control OCSP responses can create a self-signed certificate with a matching issuer name and the OCSPSigning EKU, and use it to forge OCSP responses that mark revoked certificates as valid.

This affects SSL/TLS clients using OCSP stapling, which may accept connections to servers with revoked certificates, potentially transmitting sensitive data to compromised servers. Applications using the publickey:pkixocspvalidate/5 API directly are also affected, with impact depending on usage context.

This vulnerability is associated with program files lib/publickey/src/pubkeyocsp.erl and program routines pubkeyocsp:isauthorizedresponder/3.

This issue affects OTP from OTP 27.0 until OTP 28.4.2 and 27.3.4.10 corresponding to publickey from 1.16 until 1.20.3 and 1.17.1.2, and ssl from 11.2 until 11.5.4 and 11.2.12.7.