# CVE-2026-14266: 7-Zip heap overflow in XZ decompression

Source: https://junglewise.ai/threats/cve-2026-14266-7-zip-heap-overflow-in-xz-decompression  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-29. Updated: 2026-07-29  
License: CC BY 4.0 with a link back

CVE-2026-14266 · Severity: high · CVSS 7 · Published 2026-07-29

7-Zip is a popular file compression and archiving utility used to manage various file formats. A security flaw in how it handles XZ-compressed files could allow an attacker to take control of a user's computer if the user is tricked into opening a specially crafted malicious file. This could lead to unauthorized access to personal data or the installation of harmful software.

Technologies: [7-Zip](https://junglewise.ai/threats/technologies/7-zip). Vendors: [7-Zip](https://junglewise.ai/threats/vendors/7-zip).

## Quick answers

**Is CVE-2026-14266 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-14266 being exploited in the wild.

**How severe is CVE-2026-14266?** High severity, with a CVSS score of 7, published 29 July 2026.

**Which products and versions are affected?** 7-Zip 26.01.

**Is there a fix for CVE-2026-14266?** A patch was published on 2026-07-15: Fixed in version 26.02 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-14266 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-14266?** Check whether you run 7-Zip at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A heap-based buffer overflow vulnerability (CWE-122) exists in 7-Zip within the processing of XZ chunked data. The flaw is triggered during the decompression of specially crafted XZ-compressed data, leading to memory corruption. While categorized with a local attack vector in CVSS, the vulnerability is exploitable if a user opens a malicious file or visits a malicious page (User Interaction required). Successful exploitation allows an attacker to execute arbitrary code in the context of the current process. The issue is fixed in version 26.02.

## Affected products

- 7-Zip 7-Zip 26.01

## Timeline

- 2026-06-05: other: Vulnerability reported to vendor
- 2026-07-15: advisory: Coordinated public release of advisory by ZDI
- 2026-07-15: patched: Fixed in version 26.02
- 2026-07-29: disclosed: NVD publication date

## References

- [https://www.zerodayinitiative.com/advisories/ZDI-26-444/](https://www.zerodayinitiative.com/advisories/ZDI-26-444/)
- [http://www.openwall.com/lists/oss-security/2026/07/17/12](http://www.openwall.com/lists/oss-security/2026/07/17/12)

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