CVE-2026-105280

MEDIUMCVSS 6.9/10EPSS 0.19%

Last modified

CVE-2026-105280 is a medium-severity vulnerability rated 6.9/10 on the CVSS scale. Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output. Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

Description

Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output. Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch. Hex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output. This issue affects hex: from 0.20.2 before 2.5.2.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
hexpmhex>= 0.20.2, < 2.5.2
hexpmhex>= d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c, < *

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-105280?
Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output. Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch. Hex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output. This issue affects hex: from 0.20.2 before 2.5.2.
How severe is CVE-2026-105280?
CVE-2026-105280 has a CVSS score of 6.9/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.
How do I fix CVE-2026-105280?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST