CVE-2026-48101

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.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-908 CWE-908

Affected Products

Vendor	Product	Versions
7-zip	7-zip	9.21 — 26.01

References

Advisories & Patches

https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/

Exploits

https://securitylab.github.com/advisories/GHSL-2026-115_GHSL-2026-122_7-zip/

Frequently Asked Questions

What is CVE-2026-48101? +

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. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-48101? +

CVE-2026-48101 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-48101? +

CVE-2026-48101 affects products from 7-zip, specifically: 7-zip. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-48101? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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