Bug 2508369 (CVE-2026-56389) - CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
Summary: CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious gramm...
Keywords:
Status: NEW
Alias: CVE-2026-56389
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2516215
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-29 11:01 UTC by OSIDB Bzimport
Modified: 2026-08-14 22:39 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-07-29 11:01:28 UTC 
GNU Bison allows for an execution of an arbitrary program during HTML report generation due to improper handling of grammar-defined configuration variables. A grammar file can override the executable used for the XML‑to‑HTML transformation step via %define tool.xsltproc, which is accepted without restriction and passed directly to execvp().
 
When running bison --html on a attacker-provided grammar, this behavior allows execution of an arbitrary program with the privileges of the Bison process.


Maintainers of this project were notified about this vulnerability, and fixed the issue in commit 3169c1e7a2c6acc4c59dfcf8b089896d6881925b. 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.
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