Loop with Unreachable Exit Condition ('Infinite Loop') Affecting libarchive package, versions <3.4.0-2ubuntu1.5+esm1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.02% (7th percentile)

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  • Snyk IDSNYK-UBUNTU2004-LIBARCHIVE-15688673
  • published10 Apr 2026
  • disclosed13 Mar 2026

Introduced: 13 Mar 2026

NewCVE-2026-4111  (opens in a new tab)
CWE-835  (opens in a new tab)

How to fix?

Upgrade Ubuntu:20.04 libarchive to version 3.4.0-2ubuntu1.5+esm1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libarchive package and not the libarchive package as distributed by Ubuntu. See How to fix? for Ubuntu:20.04 relevant fixed versions and status.

A flaw was identified in the RAR5 archive decompression logic of the libarchive library, specifically within the archive_read_data() processing path. When a specially crafted RAR5 archive is processed, the decompression routine may enter a state where internal logic prevents forward progress. This condition results in an infinite loop that continuously consumes CPU resources. Because the archive passes checksum validation and appears structurally valid, affected applications cannot detect the issue before processing. This can allow attackers to cause persistent denial-of-service conditions in services that automatically process archives.

CVSS Base Scores

version 3.1