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Public proof of conceptFix available

CVE-2026-23879

A public proof of concept exists; no exploitation attested.

  • Published2026-06-24
  • Fixed in1.1.3
  • WeaknessCWE-59

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.

Timeline

dates in UTC
  1. 2026-06-2420:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-23879?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-23879?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

OSV
py7zr
BranchAffectedFixed in
1.1< 1.1.31.1.3

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • miurahr py7zr
    Affected
    • = < 1.1.3no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-06-24

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • py7zrUbuntu:26.10all versions · no fixed version listed
  • py7zrUbuntu:26.04:LTSall versions · no fixed version listed
  • py7zrUbuntu:25.10all versions · no fixed version listed
  • py7zrUbuntu:24.04:LTSall versions · no fixed version listed
  • py7zrUbuntu:22.04:LTSall versions · no fixed version listed
  • py7zrDebian:14all versions · fixed in 1.1.2+dfsg-1
  • py7zrDebian:13all versions · no fixed version listed
  • py7zrDebian:12all versions · no fixed version listed

2 more package ranges on OSV.dev

Full record on NVD

Fix

  1. Update py7zr to 1.1.3

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Published
2026-06-24
Last Modified
2026-10-25
NVD status
Deferred
GitHub Advisory
GHSA-q6rc-2cgv-63h7

Frequently asked questions

What is CVE-2026-23879?

py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.

Is CVE-2026-23879 actively exploited?

A proof-of-concept exploit exists for CVE-2026-23879, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-23879?

CVE-2026-23879 has a CVSS v3 base score of 8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H.

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Sources for this record