OS Command Injection Affecting bison-runtime package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.15% (6th percentile)

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  • Snyk IDSNYK-RHEL7-BISONRUNTIME-18841736
  • published15 Aug 2026
  • disclosed29 Jul 2026

Introduced: 29 Jul 2026

NewCVE-2026-56389  (opens in a new tab)
CWE-78  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:7 bison-runtime.

NVD Description

Note: Versions mentioned in the description apply only to the upstream bison-runtime package and not the bison-runtime package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1