CVE Explorer
CVE-2026-56390
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
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"defaultStatus":"unknown","product":"Bison","repo":"https://cgit.git.savannah.gnu.org/cgit/bison.git/","vendor":"GNU","versions":[{"status":"affected","version":"3.8.2","versionType":"semver"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"LOCAL","baseScore":4.6,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"LOW","userInteraction":"ACTIVE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":…
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/metrics/0/cvssV4_0
CWE assertions
1 source assertion{"cweId":"CWE-73","description":"CWE-73 External Control of File Name or Path","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"tags":["third-party-advisory"],"url":"https://cert.pl/en/posts/2026/07/CVE-2026-56389"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/references/0
{"tags":["patch"],"url":"https://cgit.git.savannah.gnu.org/cgit/bison.git/"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/references/1
{"tags":["patch"],"url":"https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=8d101c19d4d9aaedf83a448c925513742d4efcf0"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:f0e0f7b7fe920cf3e7a4344a9a137241d61e301d78a075cbd4e87541e81fab4c · sha256:8e03896e603f913a… · /containers/cna/references/2
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.