# CVE-2026-115693: Erlang hackney improper certificate validation in SSL pinning

Source: https://junglewise.ai/threats/cve-2026-115693-improper-certificate-validation-vulnerability-in-hackney-ssl-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-26. Updated: 2026-10-26  
License: CC BY 4.0 with a link back

CVE-2026-115693 · Severity: info · Published 2026-10-26

hackney is an HTTP client library used in Erlang applications to securely connect to remote servers. A vulnerability in its certificate pinning mechanism allows an attacker on the network path to impersonate a pinned server by presenting a certificate chain rooted in a publicly trusted certificate authority, bypassing the intended private CA restriction. An attacker would need a valid certificate for the target hostname to exploit this.

Technologies: [Benoitc Hackney](https://junglewise.ai/threats/technologies/benoitc-hackney). Vendors: [Benoitc](https://junglewise.ai/threats/vendors/benoitc).

## Quick answers

**Is CVE-2026-115693 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-115693 being exploited in the wild.

**How severe is CVE-2026-115693?** Informational severity, published 26 October 2026.

**Which products and versions are affected?** Benoitc Hackney 1.24.0 to 4.8.x.

**Is there a fix for CVE-2026-115693?** Yes: fixed in hackney 4.9.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-115693 attacked?** It is attacked over the network or from the adjacent network, in a software library.

**Am I affected by CVE-2026-115693?** Check whether you run Benoitc Hackney at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in hackney 4.9.0

## Technical details

The vulnerability exists in hackney_ssl:merge_ssl_opts/3, which preserves a partial_chain callback that overrides custom certificate store settings (cacerts/cacertfile). This callback accepts any certificate chain containing a publicly trusted root, even when the connection was configured to trust only a specific private CA. The hostname verification is still enforced, requiring a valid public certificate for the target domain.

## Affected products

- benoitc hackney 1.24.0 to 4.8.x

## Timeline

- 2026-10-26: disclosed: Vulnerability publicly disclosed

## References

- [https://repo.hex.pm/](https://repo.hex.pm/)
- [https://github.com/](https://github.com/)

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