CVE-2025-31115: XZ has a heap-use-after-free bug in threaded .xz decoder

High severity · published Apr 3, 2025

CVE-2025-31115

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

8.7

CVSS

0.7%

EPSS

On KEV

Description

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.

Exploitation

Is it being used?

Exploit prediction (EPSS)0.7% · higher than 52% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

xz · tukaani-project

>= 5.3.3alpha, < 5.8.1 · source: vendor

SIMATIC S7-1500 CPU 1518-4 PN/DP MFP · Siemens

V3.1.5; V3.1.5 · source: CISA

SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP · Siemens

V3.1.5; V3.1.5 · source: CISA

SIPLUS S7-1500 CPU 1518-4 PN/DP MFP · Siemens

V3.1.5 · source: CISA

In the news

VulnerabilityHigh

XZ Utils vulnerability impacting B&R Products

View CSAF Summary An update is available that resolves vulnerability in the product versions listed as affected in the advisory. An attacker who successfully exploited this vulnerability could cause the product to stop or corrupt memory data. The following versions of XZ Utils vulnerability impacting B&R Products are affected: PPC3100 <1.8.1, 1.8.1 (CVE-2025-31115) C50 <1.8.0, 1.8.0 (CVE-2025-31115) C80 <1.8.0, 1.8.0 (CVE-2025-31115) FT50 <1.8.1, 1.8.1 (CVE-2025-31115) MT50 <1.8.1, 1.8.1 (CVE-2025-31115) T30 <1.8.0, 1.8.0 (CVE-2025-31115) T80 <1.8.0, 1.8.0 (CVE-2025-31115) T50 <1.8.1, 1.8.1 (CVE-2025-31115) CVSS Vendor Equipment Vulnerabilities v3 7.5 B&R Industrial Automation GmbH XZ Utils vulnerability impacting B&R Products Race Condition within a Thread Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: Switzerland Vulnerabilities Expand All + 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 functi...

CVE-2025-31115

Jun 30, 2026·CISA Advisories

Affected product

tukaani-project

All xz CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2025-31115

CVE.org

https://www.cve.org/CVERecord?id=CVE-2025-31115

github.com

https://github.com/tukaani-project/xz/commit/d5a2ffe41bb77b918a8c96084885d4dbe4bf6480