CVE-2026-14164

A double free issue has been identified in libarchive's RAR5 reader. During parsing of a specially crafted RAR5 archive, the filtered_buf pointer may remain stale after being freed during unpacking state reinitialization. Subsequent processing of another archive entry can trigger a second free of the same memory region, resulting in a double-free condition. Successful exploitation may cause applications using the vulnerable libarchive API to terminate unexpectedly, leading to a denial of service.

Red Hat Product Security has assessed this CVE as 7.5 CVSS with Moderate security Impact. This assessment reflects the library's typical deployment within enterprise software, where libarchive is frequently embedded into automated, network-accessible services that receive and process archives originating from remote sources. In these environments, a specially crafted RAR5 archive may be delivered and processed automatically without requiring direct user interaction, allowing a remote attacker to trigger the vulnerability and cause the affected application or service processing the archive to terminate unexpectedly, resulting in a denial of service.

From a standalone library perspective, however, the vulnerable code is only reached when an application opens and processes a crafted RAR5 archive. Evaluating libarchive in isolation, without considering downstream deployment models, the vulnerability more closely aligns with a CVSS score of 5.5-CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H (Moderate), reflecting an Attack Vector of Local (AV:L) and User Interaction Required (UI:R). This is because the crafted archive must first be delivered to and processed by a local application before the vulnerable parsing logic is executed.

Red Hat's assigned score instead reflects the operational deployment of libarchive in automated, network-facing workloads in downstream environment models rather than the standalone library in isolation.

This vulnerability only affects libarchive releases that include support for the RAR5 archive format. RAR5 support was first introduced upstream in libarchive 3.4.0 (https://github.com/libarchive/libarchive/wiki/ReleaseNotes#libarchive-340). Earlier libarchive releases do not contain the vulnerable RAR5 parsing code and are therefore not affected.

Red Hat Enterprise Linux 6, 7, and 8 ship Libarchive versions prior to v3.4.0 that do not include RAR5 support and are therefore not affected.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability. Customers are advised to apply the appropriate security update once it becomes available.