CVE-2026-56389
published 2026-07-29CVE-2026-56389: GNU Bison allows for an execution of an arbitrary program during HTML report generation due to improper handling of grammar-defined configuration variables. A…
PriorityP344high8.6CVSS 3.1
AVLACLPRNUIRSCCHIHAH
EPSS
0.16%
5.3th percentile
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.
Affected
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| gnu | bison | — | — |
| gnu | bison | — | — |
CVSS provenance
nvdv3.18.6HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
nvdv4.06.8MEDIUMCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:H/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vendor_redhat6.8MEDIUM
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GHSA
GNU Bison allows for an execution of an arbitrary program during HTML report generation due to improper handling of grammar-defined configuration variables.
ghsa_unreviewed·2026-07-29
CVE-2026-56389 [MEDIUM] CWE-78 GNU Bison allows for an execution of an arbitrary program during HTML report generation due to improper handling of grammar-defined configuration variables.
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
Red Hat
bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
vendor_redhat·2026-07-29·CVSS 6.8
CVE-2026-56389 [MEDIUM] CWE-78 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
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 confir
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file [fedora-all]
bugzilla·2026-08-14·CVSS 6.8
CVE-2026-56389 [MEDIUM] CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file [fedora-all]
CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
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
Bugzilla
CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
bugzilla·2026-07-29·CVSS 6.8
CVE-2026-56389 [MEDIUM] CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
CVE-2026-56389 bison: GNU Bison: Arbitrary Code Execution via malicious grammar file
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
2026-07-29
Published