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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2025-31115

29
FAUCET Score

CVE-2025-31115 is a critical vulnerability in XZ Utils versions 5.3.3alpha to 5.8.0, specifically impacting the multithreaded .xz decoder in liblzma. Invalid input can lead to crashes, heap use-after-free, and writes to arbitrary memory locations, affecting applications and libraries utilizing the lzma_stream_decoder_mt function. With a CVSS score of 8.7 (HIGH), this vulnerability presents a significant risk due to its network-based attack vector and low attack complexity, potentially leading to high availability impact. While no active exploitation, public exploit code, or significant community discussion has been observed, a fix is available in XZ Utils 5.8.1 and as a standalone patch for affected versions.

Impacted Technologies

VendorProductVersion(s)CPE
Tukaani-ProjectXz
>= 5.3.3alpha, < 5.8.1CNA affected

CVSS Data

CVSS version used by this source: 4.0

8.7HIGH

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
NONE
VS Integrity
NONE
VS Availability
HIGH
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.65%
Probability of exploitation in next 30 days
EPSS Percentile
47.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0065 is in the 24th percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

microsoftpatch availablevia msrc
Product: 19442-17084Fixed in: 5.4.4-2
microsoftpatch availablevia msrc
Product: azl3 xz 5.4.4-2 on Azure Linux 3.0Fixed in: 5.4.4-2
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 10Fixed in: xz-1:5.6.2-4.el10_0
View patch

Vendor Advisories (2)

microsoft2025-Apr/CVE-2025-31115Important

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

Apr 8, 2025
redhatCVE-2025-31115Important

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

Apr 3, 2025

References

cert-portal.siemens.com / productcert/html/ssa-082556.html
openwall.com / lists/oss-security/2025/04/03/1
openwall.com / lists/oss-security/2025/04/03/2
openwall.com / lists/oss-security/2025/04/03/3
github.com / tukaani-project/xz/commit/d5a2ffe41bb77b918a8c96084885d4dbe4bf6480
github.com / tukaani-project/xz/security/advisories/GHSA-6cc8-p5mm-29w2
tukaani.org / xz/xz-cve-2025-31115.patch