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

Status: published. Published: 2026-10-12. Updated: 2026-11-11.

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.

## Remediation

- fix: Upgrade Hex to 2.5.2 or later, for example with mix local.hex. A retired locked release then no longer lifts the release-age cooldown for its package. A locked release with a security advisory still lifts it for its package and the direct dependencies of the locked release, only in the repository the package is locked from. (source: CNA: EEF)
- workaround: Enforce the cooldown through an organization dependency policy instead of the local cooldown setting, or run mix hex.audit before mix deps.update and don't update a package whose locked release was retired until its replacement has been reviewed. (source: CNA: EEF)
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: EEF) — https://github.com/hexpm/hex/commit/eed2bdf85320ae9e244629511c03f5f3f8c5d0b5
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: EEF) — https://github.com/hexpm/hex/commit/1b6fddfeadd98ed26a143f60356efade0494e2ae

## Affected products and versions

- hexpm / hex (hex): ≥ 2.5.0; < 2.5.2 (affected, semver). Source: CNA: EEF
- hexpm / hex (hexpm/hex): ≥ b4e665d46be8a5f81e8cbbe4c3a67058a19cf133; < * (affected, git); unaffected at eed2bdf85320ae9e244629511c03f5f3f8c5d0b5; unaffected at 1b6fddfeadd98ed26a143f60356efade0494e2ae. Source: CNA: EEF

## Severity and prioritization

- CVSS 4.0: 7.1 (high); 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; source: CNA: EEF

- CISA KEV: No listing in collected sources

- EPSS: 0.36% as of 2026-11-10; percentile 30.32%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-693

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/hexpm/hex/security/advisories/GHSA-pqhp-5x9x-69h7 (CNA: EEF; related, vendor-advisory)

- https://cna.erlef.org/cves/CVE-2026-105668.html (CNA: EEF; related)

- https://osv.dev/vulnerability/EEF-CVE-2026-105668 (CNA: EEF; related)

- https://github.com/hexpm/hex/commit/b4e665d46be8a5f81e8cbbe4c3a67058a19cf133 (CNA: EEF; related)

- https://github.com/hexpm/hex/commit/eed2bdf85320ae9e244629511c03f5f3f8c5d0b5 (CNA: EEF; patch)

- https://github.com/hexpm/hex/commit/1b6fddfeadd98ed26a143f60356efade0494e2ae (CNA: EEF; patch)

## Provenance

- CNA: EEF: https://www.cve.org/CVERecord?id=CVE-2026-105668; retrieved 2026-11-11; source updated 2026-11-11

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-105668; retrieved 2026-11-11; source updated Not reported

Revision: 33320ff9c875f6a5b1ea178b9c1504091068fbc9bb1fb775b2e02c1065e1cad8

Canonical: https://y2.dev/cve/CVE-2026-105668

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