CVE-2026-55783Public exploit

Process crash via NULL archive index dereference

Published Jul 10, 2026 · Updated Jul 10, 2026

NULL pointer dereference in NanaZip before 6.5.1749.0 allows attackers to crash the process by testing or extracting an affected archive. Each of seven NanaZip.Codecs archive Extract handlers sends the unguarded caller-supplied index array to GetStream after the engine sets that array to NULL for all-items mode. Exploitation requires opening a WebAssembly, ElectronAsar, Zealfs, Romfs, Ufs, Littlefs, or DotNetSingleFile archive and invoking Test or Extract all; the resulting access violation terminates the NanaZip process without affecting confidentiality or integrity.

CVSS severity2.4
Low
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in NanaZip before 6.5.1749.0 allows attackers to crash the process by testing or extracting an affected archive. Each of seven NanaZip.Codecs archive Extract handlers sends the unguarded caller-supplied index array to GetStream after the engine sets that array to NULL for all-items mode. Exploitation requires opening a WebAssembly, ElectronAsar, Zealfs, Romfs, Ufs, Littlefs, or DotNetSingleFile archive and invoking Test or Extract all; the resulting access violation terminates the NanaZip process without affecting confidentiality or integrity.

The record

CVE
CVE-2026-55783
Published
Jul 10, 2026
Updated
Jul 10, 2026
Vendor
M2-Team
Product
NanaZip
Classifications
CWE-476, T1204.002
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6.5.1749.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

M2-Team · NanaZipversion=< 6.5.1749.0

Published CVSS scores

2.4GitHubCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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