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CVE-2026-104086VulnerabilityPublished Updated

P7zip: 7-Zip before 26.03 contains an uninitialized memory disclosure vulnerability in the SquashFS v4 archive handler

Affects p7zipSource GCVE Database

0
Authoritative record:CVE-2026-104086· Medium 6.8

Not known to be exploited · CVSS 6.8 Medium.

Data as of 28 Oct 2026, 22:31 UTC

CVSS 4.0 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 26.107zippkg:deb/ubuntu/7zip?arch=source&distro=stonkingOther threatsAffected
  • 26.00+dfsg-1 – 26.02+dfsg-2
5 affected builds
Fixed in–
Ubuntu 26.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=resoluteOther threatsAffected
  • 25.01+dfsg-2 – 26.00+dfsg-1
5 affected builds
Fixed in–
Ubuntu 24.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=nobleOther threatsAffected
  • =16.02+dfsg-8
  • =16.02+transitional.1
Fixed in–
Ubuntu Pro 24.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/nobleOther threatsAffected
  • 23.01+dfsg-3 – 23.01+dfsg-11ubuntu0.1~esm1
5 affected builds
Fixed in–
Ubuntu 22.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=jammyOther threatsAffected
  • =16.02+dfsg-8
Fixed in–
Ubuntu Pro 22.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/jammyOther threatsAffected
  • 21.03~beta+dfsg-6 – 21.07+dfsg-4ubuntu0.1~esm1
8 affected builds
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

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