Allocation of resources without limits in Erlang/OTP public_key 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 public_key:pkix_path_validation/3, the certificate policy tree maintained by pubkey_policy_tree 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 pubkey_policy_tree:add_leaves/2 and pubkey_policy_tree:add_leaf_siblings/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 X509_verify_cert policy tree DoS. This vulnerability is associated with program files lib/public_key/src/pubkey_policy_tree.erl and program routines pubkey_policy_tree:add_leaves/2 and pubkey_policy_tree:add_leaf_siblings/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 public_key from 1.15 before 1.21.4, 1.20.3.4 and 1.17.1.5.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Allocation of resources without limits in Erlang/OTP public_key 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 public_key:pkix_path_validation/3, the     certificate policy tree maintained by pubkey_policy_tree 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 pubkey_policy_tree:add_leaves/2 and pubkey_policy_tree:add_leaf_siblings/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     X509_verify_cert policy tree DoS. This vulnerability is associated with program files     lib/public_key/src/pubkey_policy_tree.erl and program routines pubkey_policy_tree:add_leaves/2 and     pubkey_policy_tree:add_leaf_siblings/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 public_key from 1.15 before 1.21.4, 1.20.3.4 and 1.17.1.5.
    (CVE-2026-59251)

Note that Nessus relies on the presence of the package as reported by the vendor.

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the 445d674f-89e1-11f1-b35c-4c526214c986 advisory.

    https://github.com/erlang/otp/security/advisories/GHSA-622p-qfh6-c352 reports:
    A remote attacker can trigger a denial of service through               TLS certificate handling. By sending a specially crafted               certificate chain with multiple certificate policies at each               level, the policy tree expands exponentially during validation,               growing as M^K nodes (where M is the number of policies per               certificate and K is the chain depth). This pins schedulers               and exhausts memory without any authentication. Any               application using SSL/TLS that validates certificate paths is               affected, as are direct calls to               public_key:pkix_path_validation/3.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
330394	Linux Distros Unpatched Vulnerability : CVE-2026-59251	Nessus	Misc.	high
330272	FreeBSD : Erlang/OTP -- denial of service via exponential certificate policy tree growth (445d674f-89e1-11f1-b35c-4c526214c986)	Nessus	FreeBSD Local Security Checks	high

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