CVE-2026-27117 bit7z has a path traversal vulnerability
Attackers can write arbitrary files outside the extraction directory via malicious archives, potentially overwriting binaries or configs in applications using bit7z.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-27117?
CVE-2026-27117 is a medium-severity path traversal vulnerability in rikyoz bit7z, published on 24 Feb 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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 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.
Which versions are affected by CVE-2026-27117?
It affects 1 product.
Products include Rikyoz Bit7z.
How do I fix CVE-2026-27117?
No fix has been published for CVE-2026-27117 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-27117 being exploited?
There is no known exploitation of CVE-2026-27117 in the wild and no public exploit code.
Sources
Also known as GHSA-qvjh-hhw4-3gx9.