CVE-2026-55781

2.4 LOW 0.2% exploit odds Fix listed Denial of service OS & kernel

What it is

NanaZip is the 7-Zip derivative intended for the modern Windows experience. Prior to 6.5.1749.0, NanaZip's UFS and FFS image handler in NanaZip.Codecs.Archive.Ufs.cpp validates the superblock block size only against the MINBSIZE lower bound and does not validate the fs_fsize fragment size, allowing attacker-controlled 32-bit fields to flow into indirect-block, directory, and extraction buffer allocations. A tiny crafted UFS image can force multi-gigabyte allocations during open or extraction, causing memory exhaustion or process termination. This issue is fixed in version 6.5.1749.0.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account, but needs a user to act. Limited direct impact.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-10 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-25 15:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 2.4 LOW (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-07-10 17:16 UTC
Last modified: 2026-10-25 15:10 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-400 · Uncontrolled resource consumption
Record status: Deferred

Attack profile CVSS 4.0 · 2.4

Attack vector: Local
Complexity: Low
Attack requirements: None
Privileges needed: Low
User interaction: Passive
Confidentiality: None
Integrity: None
Availability: Low

Raw vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-55781.md and follow it. Check whether this project is affected by CVE-2026-55781. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record