CVE catalog
CVE-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 grammar file can override the executable
- Severity
- Medium · CVSS 6.8
CVSS: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 - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.22% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | bison | sid | 2:3.8.2+dfsg-1 | vulnerable |
| Debian | bison | forky | 2:3.8.2+dfsg-1 | vulnerable |
| Debian | bison | trixie | 2:3.8.2+dfsg-1 | vulnerable |
| Debian | bison | bookworm | 2:3.8.2+dfsg-1 | vulnerable |
| Cpe | bison | Not reported | Not reported | unknown |
| Ubuntu | bison | noble | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | fixed |
| Ubuntu | libbison-dev | noble | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | fixed |
| Ubuntu | bison | 22.04 | 2:3.7.6+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1ubuntu0.22.04.1 | fixed |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1build2 | vulnerable |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | fixed |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1build3 | vulnerable |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1build4 | vulnerable |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1ubuntu0.26.04.1 | fixed |
| Ubuntu | bison | 22.04 | 2:3.7.6+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 22.04 | 2:3.8.2+dfsg-1ubuntu0.22.04.1 | fixed |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1build1 | vulnerable |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1build2 | vulnerable |
| Ubuntu | bison | 24.04 | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | fixed |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1build3 | vulnerable |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1build4 | vulnerable |
| Ubuntu | bison | 26.04 | 2:3.8.2+dfsg-1ubuntu0.26.04.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | bison | source | sid | (unfixed) | not yet assigned | Not reported | [1143158] |
| Debian | bison | source | forky | (unfixed) | not yet assigned | Not reported | [1143158] |
| Debian | bison | source | trixie | (unfixed) | not yet assigned | Not reported | [1143158] |
| Debian | bison | source | bookworm | (unfixed) | not yet assigned | Not reported | [1143158] |
| Ubuntu | bison | deb | noble | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | Not reported | Not reported | Not reported |
| Ubuntu | libbison-dev | deb | noble | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | Not reported | Not reported | Not reported |
| Ubuntu | bison | deb | 22.04 | 2:3.8.2+dfsg-1ubuntu0.22.04.1 | Not reported | USN-8777-1 | Not reported |
| Ubuntu | bison | deb | 24.04 | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | Not reported | USN-8777-1 | Not reported |
| Ubuntu | bison | deb | 26.04 | 2:3.8.2+dfsg-1ubuntu0.26.04.1 | Not reported | USN-8777-1 | Not reported |
| Ubuntu | bison | deb | 22.04 | 2:3.8.2+dfsg-1ubuntu0.22.04.1 | Not reported | UBUNTU-CVE-2026-56389 | Not reported |
| Ubuntu | bison | deb | 24.04 | 2:3.8.2+dfsg-1ubuntu0.24.04.1 | Not reported | UBUNTU-CVE-2026-56389 | Not reported |
| Ubuntu | bison | deb | 26.04 | 2:3.8.2+dfsg-1ubuntu0.26.04.1 | Not reported | UBUNTU-CVE-2026-56389 | Not reported |
Notes
[trixie] bison: Minor issue [bookworm] bison: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [bison]Affected
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b1· amd64 · bookwormAffected
nvd · bison · debian · bookworm; nvd · bison · debian · 12
2:3.8.2+dfsg-1+b1· arm64 · bookwormAffected
nvd · bison · debian · bookworm; nvd · bison · debian · 12
- [libbison-dev]Affected
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b1· amd64 · bookwormAffected
nvd · bison · debian · bookworm; nvd · bison · debian · 12
2:3.8.2+dfsg-1+b1· arm64 · bookwormAffected
nvd · bison · debian · bookworm; nvd · bison · debian · 12
[Debian 13 (Trixie)]
- [bison]Affected
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b2· amd64 · trixieAffected
nvd · bison · debian · 13
2:3.8.2+dfsg-1+b2· arm64 · trixieAffected
nvd · bison · debian · 13
- [libbison-dev]Affected
Source package: [bison]
Details (2)
2:3.8.2+dfsg-1+b2· amd64 · trixieAffected
nvd · bison · debian · 13
2:3.8.2+dfsg-1+b2· arm64 · trixieAffected
nvd · bison · debian · 13
Observed:
References
- [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=3169c1e7a2c6acc4c59dfcf8b089896d6881925b]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-56389]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-56389]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-56389]
- [https://osv.dev/vulnerability/USN-8777-1]
- [https://security-tracker.debian.org/tracker/CVE-2026-56389]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-56389.json]
- [https://ubuntu.com/security/notices/USN-8777-1]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [Ubuntu Security Notices (USN)]