CVE-2026-56390
MEDIUM
4,6
Source: [email protected]
Attack Vector: local
Attack Complexity: low
Privileges Required: none
User Interaction: active
Confidentiality: N/A
Integrity: N/A
Availability: N/A
Description
AI Translation Available
GNU Bison improperly handles grammar‑defined output paths. Grammar directives such as %output and %header allow specifying file paths, which are accepted without restriction and override caller‑supplied output options.
When processing attacker-supplied grammar, this behavior allows directing generated files to arbitrary writable locations on the filesystem, potentially overwriting existing files accessible to the Bison process.
Maintainers of this project were notified about this vulnerability, and fixed the issue in commit 8d101c19d4d9aaedf83a448c925513742d4efcf0. However, they did not provide vulnerable version range. Version 3.8.2 was tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.
73
External Control of File Name or Path
DraftCommon Consequences
Security Scopes Affected:
Integrity
Confidentiality
Availability
Potential Impacts:
Read Files Or Directories
Modify Files Or Directories
Execute Unauthorized Code Or Commands
Dos: Crash, Exit, Or Restart
Dos: Resource Consumption (Other)
Applicable Platforms
Operating Systems:
Unix, Windows, macOS
https://cert.pl/en/posts/2026/07/CVE-2026-56389
https://cgit.git.savannah.gnu.org/cgit/bison.git/
https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=8d101c19d4d9aaedf83…