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CVE-2026-105668

Description

A flaw was found in hex. This vulnerability allows an attacker with package owner privileges to bypass release-age cooldown security controls when publishing a new package release. By retiring an existing package release, the attacker triggers an automatic cooldown bypass, causing downstream dependency updates to immediately pull the newly published release without observing the required waiting period. Consequently, this flaw can enable the rapid deployment of unvetted or malicious dependencies into downstream environments.

Statement

A flaw of moderate impact was found in hex, the package manager for the Elixir/Erlang ecosystem, which Red Hat tracks only in its community Fedora and EPEL streams. Hex's release-age cooldown (the cooldown config option or HEX_COOLDOWN environment variable) withholds versions younger than the configured age during dependency resolution so that newly published, potentially malicious releases are not pulled into projects immediately. When the release of a package locked in mix.lock is retired or carries 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. Because retiring a release requires the same package owner permission as publishing one, an attacker who controls or has compromised a package owner account can publish a malicious release, retire the currently locked release, and have the next mix deps.update that unlocks the package select the new release regardless of its age, enabling the rapid deployment of unvetted or malicious dependency code into downstream environments. The bypass check in Hex.Registry.Cooldown.versions/2 matches by package name alone, so it also covers packages with the same name in other repositories; cooldowns enforced through an organization dependency policy are not affected. Exploitation requires high privileges (package owner) and user interaction (a victim running a dependency update), which is why Red Hat rates this flaw Moderate with a CVSS 3.1 score of 6.8, while the upstream CVEORG record scores it Important at CVSS 4.0 score 7.1; the difference stems from CVSS version and metric differences (attack complexity and user interaction) rather than a substantive disagreement about impact. No Red Hat-shipped products are affected; the tracked Fedora and EPEL community entries are affected with delegated resolution, meaning a fix is being pursued through the community maintainers.

Mitigation

Workarounds are available. Enforce the cooldown through a Hex organization dependency policy instead of the local `cooldown` setting or `HEX_COOLDOWN` environment variable, since policy-based cooldowns do not consult the bypass set and are not affected. Alternatively, run `mix hex.audit` before `mix deps.update` and do not update a package whose locked release was retired until its replacement release has been reviewed. Upgrading to the fixed upstream Hex release (2.5.2 or later) resolves the issue; for the tracked community Fedora and EPEL streams, apply updated packages once the community maintainers ship them.

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score6.8N/AN/A
Attack VectorNetworkN/AN/A
Attack ComplexityLowN/AN/A
Privileges RequiredHighN/AN/A
User InteractionRequiredN/AN/A
ScopeUnchangedN/AN/A
ConfidentialityHighN/AN/A
Integrity ImpactHighN/AN/A
Availability ImpactHighN/AN/A

Vector

Red Hat: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H

Frequently Asked Questions

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