CVE-2026-27117

Arbitrary file write via unsanitized archive paths

Published Feb 24, 2026 · Updated Feb 24, 2026

Path traversal in bit7z before 4.0.11 allows attackers to write files outside the extraction directory via a crafted archive. FileExtractCallback joins 7-Zip-supplied relative or absolute entry names to the output path and restores symbolic links without constraining the resolved destination. Exploitation requires an application to extract an unverified attacker-supplied archive and grants file-write access with that process's filesystem privileges.

CVSS severity5.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in bit7z before 4.0.11 allows attackers to write files outside the extraction directory via a crafted archive. FileExtractCallback joins 7-Zip-supplied relative or absolute entry names to the output path and restores symbolic links without constraining the resolved destination. Exploitation requires an application to extract an unverified attacker-supplied archive and grants file-write access with that process's filesystem privileges.

The record

CVE
CVE-2026-27117
Published
Feb 24, 2026
Updated
Feb 24, 2026
Vendor
Riccardo Ostani
Product
bit7z
Classifications
CWE-23, CWE-22, CWE-36, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 24, 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=< 4.0.11

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Riccardo Ostani · bit7zversion=< 4.0.11

Published CVSS scores

5.5GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
7.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-23Relative Path Traversal
CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-36Absolute Path Traversal
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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