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HIGH CWE-366

CVE-2025-31115

XZ has a heap-use-after-free bug in threaded .xz decoder

Tukaani·xz

8.7/ 10
CVSS 4.0
High severity
0.68%
EPSS exploit odds
Chance of exploitation in the next 30 days
Higher than 53% of all CVEs
Not listed
CISA KEV catalog
No confirmed in-the-wild exploitation on CISA's list.
Timeline
Published
Apr 3, 2025
Updated
Oct 15, 2026
First covered
Jul 3, 2026
Latest story
4 months ago

Summary

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.

CWE-366Race Condition within a Thread

Attack profile

Attack vectorNetwork
ComplexityLow
RequirementsNone
PrivilegesNone
User interactionNone
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Affected products

  • Tukaani xz>= 5.3.3alpha, < 5.8.1

References

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