Use After Free in Tukaani-Project Xz
CVE-2025-31115
XZ Utils provide a general-purpose data-compression library plus command-line tools. In XZ Utils 5.3.3alpha to 5.8.0, the multithreaded .xz decoder in liblzma has a bug where invalid input can at least result in a crash. The effects include heap use after free and writing to an address based on the null pointer plus an offset. Applications and libraries that use the lzma_stream_decoder_mt function are affected. The bug has been fixed in XZ Utils 5.8.1, and the fix has been committed to the v5.4, v5.6, v5.8, and master branches in the xz Git repository. No new release packages will be made from the old stable branches, but a standalone patch is available that applies to all affected releases.
EPSS: 0.007 (48.8th percentile) — read the EPSS interpretation.
Affected products
- Tukaani-project Xz — versions >= 5.3.3alpha, < 5.8.1
Weakness classification (CWE)
Public proof-of-concept exploits
References
- https://github.com/tukaani-project/xz/security/advisories/GHSA-6cc8-p5mm-29w2 (x_refsource_CONFIRM)
- https://github.com/tukaani-project/xz/commit/d5a2ffe41bb77b918a8c96084885d4dbe4bf6480 (x_refsource_MISC)
- https://tukaani.org/xz/xz-cve-2025-31115.patch (x_refsource_MISC)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
- 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
Frequently asked questions
- What is CVE-2025-31115?
- CVE-2025-31115 is a vulnerability in Tukaani-Project Xz, classified under Race Condition within a Thread. Published 2025-04-03.
- Is CVE-2025-31115 known to be exploited?
- 5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.