CVE-2026-48101: mcmilk 7-Zip · Use of Uninitialized Resource
Affects mcmilk 7-ZipSource CVE Database V5
Not known to be exploited · CVSS 6.5 Medium : upgrade to 26.01 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 20% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 26.01
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 5 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 Oct 2026.
What to do
Upgrade mcmilk 7-Zip to 26.01.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| mcmilk7-Zip | Affected
| Fixed in
|
AI-suggested
Version 26.0.1 of 7-Zip fixes this vulnerability by properly handling buffer initialization and read operations in the UEFI capsule parser. Users should upgrade to 7-Zip 26.0.1 or later to remediate this issue. Patch status is not explicitly confirmed in the vendor advisory, but the description states version 26.0.1 fixes the issue. No other mitigations are indicated.
Description
7-Zip is a file archiver with a high compression ratio. Versions 9.21 through 26.00 contain an An uninitialized memory disclosure vulnerability in the UEFI capsule (.scap) parser in 7-Zip. The OpenCapsule function allocates a heap buffer of attacker-declared CapsuleImageSize (up to 1 GiB) without zero-initialization, then reads the file contents into it with ReadStream_FALSE whose return value is silently discarded. If the file is truncated, the unread tail of the buffer retains uninitialized heap memory, which is then exposed as extracted file content via GetStream. Version 26.0.1 fixes the issue.