P7zip: 7-Zip before 26.03 contains an uninitialized memory disclosure vulnerability in the SquashFS v4 archive handler
Affects p7zipSource GCVE Database
Not known to be exploited · CVSS 6.8 Medium.
Data as of 28 Oct 2026, 22:31 UTC
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 14 Oct 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 26.107zippkg:deb/ubuntu/7zip?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/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.
Description
7-Zip before 26.03 contains an uninitialized memory disclosure vulnerability in the SquashFS v4 archive handler (SquashfsHandler.cpp) that allows attackers to leak heap memory by crafting a malicious archive where the superblock’s no_ids field is set so that the final metadata block’s expected size is miscomputed and bypasses the size validation check. By listing or extracting the crafted archive, attackers can cause the application to return uninitialized heap memory as the kpidUserId and kpidGroupId properties, exposing potentially sensitive process memory contents to the user.
References
- ubuntu.com/security/CVE-2026-104086 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-104086 (opens in a new tab)
- 7-zip.org (opens in a new tab)
- sourceforge.net/p/sevenzip/discussion/45797/thread/db6922e1d0/ (opens in a new tab)
- vulncheck.com/advisories/7-zip-squashfs-uninitialized-memory-disclosure-via-uid-gid-table (opens in a new tab)