CVE-2026-115693 Custom cacerts or cacertfile do not restrict trust to the pinned CA in hackney
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115693?
CVE-2026-115693 is a critical vulnerability in benoitc hackney, published on 26 Oct 2026.
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.
Weakness: CWE-295
Which versions are affected by CVE-2026-115693?
1 open source package ship an affected version, including hackney.
| Package | Affected | Fixed in |
|---|---|---|
hackney Hex | From 1.24.0 | 4.9.0 |
How do I fix CVE-2026-115693?
Upgrade hackney to 4.9.0 or later.
Is CVE-2026-115693 being exploited?
There is no known exploitation of CVE-2026-115693 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-115693, GHSA-g7gg-9jhv-68h6.