Raw vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:NSummary
CVE-2026-27117 is a medium-severity Path Traversal (CWE-22) vulnerability in Rikyoz Bit7Z. Its CVSS base score is 5.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 23th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-27117 is a path traversal vulnerability, commonly known as "Zip Slip," affecting bit7z, a cross-platform C++ static library used for compression and extraction of archive files. In versions prior to 4.0.11, the library's archive extraction functionality fails to adequately validate file paths in archive entries. This allows files to be written outside the intended extraction directory through three mechanisms: relative path traversal, absolute path traversal, and symbolic link traversal.
The vulnerability can be exploited by an attacker who provides a malicious archive to any application that uses bit7z to extract untrusted archives. Exploitation requires local access (AV:L) with no privileges (PR:N) but involves user interaction (UI:R), such as prompting a user to extract the archive. Successful exploitation enables arbitrary file writes with the privileges of the extracting process, potentially overwriting application binaries, configuration files, or other sensitive data. While it does not directly enable file reading, secondary confidentiality risks may arise if applications serve or display extracted files, particularly those containing attacker-created symlinks.
The bit7z project has addressed the issue in version 4.0.11, with fixes implemented via specific commits that enhance path validation during extraction. The security advisory (GHSA-qvjh-hhw4-3gx9) and release notes recommend immediate upgrading where possible. Alternative mitigations include manually validating each entry's destination path before writing files, running extraction processes with least privilege, and extracting untrusted archives into a sandboxed directory.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-8571
Vulnerability Data
bit7z is a cross-platform C++ static library that allows the compression/extraction of archive files. Prior to version 4.0.11, a path traversal vulnerability ("Zip Slip") exists in bit7z's archive extraction functionality. The library does not adequately validate file paths contained in…
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archive entries, allowing files to be written outside the intended extraction directory through three distinct mechanisms: relative path traversal, absolute path traversal, and symbolic link traversal. An attacker can exploit this by providing a malicious archive to any application that uses bit7z to extract untrusted archives. Successful exploitation results in arbitrary file write with the privileges of the process performing the extraction. This could lead to overwriting of application binaries, configuration files, or other sensitive data. The vulnerability does not directly enable reading of file contents; the confidentiality impact is limited to the calling application's own behavior after extraction. However, applications that subsequently serve or display extracted files may face secondary confidentiality risks from attacker-created symlinks. Fixes have been released in version 4.0.11. If upgrading is not immediately possible, users can mitigate the vulnerability by validating each entry's destination path before writing. Other mitigations include running extraction with least privilege and extracting untrusted archives in a sandboxed directory.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Information-flow rules can be configured to reject traversals that would move data outside an approved directory boundary.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Secure-engineering principles require safe pathname construction and input neutralization before any file operation.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require input validation and path sanitization that prevent relative traversal.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.