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[ CVE-2026-115693 · Published 26 Oct 2026 ]

Vulnerability in benoitc hackney

CVSS 9.1 EPSS <1%No fix listed yet

[ Why it matters ]Priority signals

  • Critical severity: CVSS 9.1

[ Description ]Official description

Improper Certificate Validation vulnerability in hackney_ssl in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds {partial_chain, fun hackney_ssl:partial_chain/1} to every verify_peer configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured cacerts. hackney_ssl:merge_ssl_opts/3 kept the callback when the caller replaced the trust store with cacerts or cacertfile in ssl_options, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root. The hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname. This issue affects hackney: from 1.24.0 before 4.9.0.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References