Py7zr: Prior to 1.1.3, PackInfo._read()
Affects py7zrSource GCVE Database
Not known to be exploited · CVSS 8.7 High · fixed in 1.1.3 : patch py7zr soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.1.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 8 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10py7zrpkg:deb/ubuntu/py7zr?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSpy7zrpkg:deb/ubuntu/py7zr?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10py7zrpkg:deb/ubuntu/py7zr?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSpy7zrpkg:deb/ubuntu/py7zr?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSpy7zrpkg:deb/ubuntu/py7zr?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade Py7zr to version 1.1.3 or later, where this vulnerability is fixed. No other mitigation is indicated or required.
Description
Py7zr versions prior to 1.1.3 have a vulnerability in the PackInfo._read() function where an inefficient O(n^2) algorithm can cause excessive CPU consumption when processing crafted .7z archives. This can lead to denial of service by resource exhaustion during archive initialization. The issue is fixed in version 1.1.3.
References
- ubuntu.com/security/CVE-2026-55206 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-55206 (opens in a new tab)
- github.com/miurahr/py7zr/commit/d7aa3a197d15c75a65b24f796d3a69f83806d3f8 (opens in a new tab)
- github.com/miurahr/py7zr/releases/tag/v1.1.3 (opens in a new tab)
- github.com/miurahr/py7zr/security/advisories/GHSA-h4gh-22qq-72r7 (opens in a new tab)