# CVE-2026-105280: Hex improper validation of integrity check value in package fetch

Source: https://junglewise.ai/threats/cve-2026-105280-improper-validation-of-integrity-check-value-vulnerability-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-105280 · Severity: info · Published 2026-10-12

Hex is a package manager for the Elixir programming language. When developers use the mix hex.package fetch command with --output - to pipe packages to other tools, an attacker operating a package mirror can inject modified or malicious code that gets written to standard output without cryptographic verification, allowing arbitrary code execution through downstream processing of the package.

Technologies: [Hexpm Hex](https://junglewise.ai/threats/technologies/hexpm-hex). Vendors: [Hexpm](https://junglewise.ai/threats/vendors/hexpm).

## Quick answers

**Is CVE-2026-105280 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-105280 being exploited in the wild.

**How severe is CVE-2026-105280?** Informational severity, published 12 October 2026.

**Which products and versions are affected?** Hexpm Hex 0.20.2 before 2.5.2.

**Is there a fix for CVE-2026-105280?** Yes: fixed in Hex 2.5.2. Until then: Write the tarball to a file using --output FILE instead of standard output, which performs checksum verification before writing. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-105280 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-105280?** Check whether you run Hexpm Hex 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 Hex 2.5.2

Write the tarball to a file using --output FILE instead of standard output, which performs checksum verification before writing.

## Technical details

The mix hex.package fetch command with --output - writes bytes from Hex.SCM.fetch/3 directly to standard output without verifying the tarball's checksum against the signed registry. The file-based output path performs this verification, but the standard output path skips it. Additionally, diagnostic messages printed to standard output during the fetch can include arbitrary content from mirror error responses, allowing a malicious mirror to inject a tar archive that gets unpacked before checksum verification fails.

## Affected products

- hexpm Hex 0.20.2 before 2.5.2

## Timeline

- 2026-10-12: disclosed

## References

- [https://github.com/](https://github.com/)
- [https://cna.erlef.org/cves/CVE-2026-105280.html](https://cna.erlef.org/cves/CVE-2026-105280.html)

## Related threats

- [Erlang OTP erl_tar infinite loop in GNU sparse member handling](https://junglewise.ai/threats/cve-2026-96596-loop-with-unreachable-exit-condition-infinite-loop-vulnerability)
- [hexpm hex_core memory exhaustion via compressed data amplification](https://junglewise.ai/threats/cve-2026-105274-improper-handling-of-highly-compressed-data-data-amplification)
- [Hex package manager data amplification via compressed responses](https://junglewise.ai/threats/cve-2026-96618-improper-handling-of-highly-compressed-data-data-amplification)
- [Hex path traversal in unvalidated dependency app names](https://junglewise.ai/threats/cve-2026-96612-improper-limitation-of-a-pathname-to-a-restricted-directory-path)
- [Hex terminal escape sequence injection via package metadata](https://junglewise.ai/threats/cve-2026-81856-improper-neutralization-of-escape-meta-or-control-sequences)