CVE Explorer

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 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.

Lifecycle PUBLISHED1 preserved revisionFact urn:baitaphish:canonical-cve-fact-revision:v2:c5f7104f499e7bfaff10aaffe0f7a30351fb240dc9dd75808e9cdf07fa9e696a

Known exploited

Not asserted

Disputed

Stale source

Conflicts

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_v5affected
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /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":6.8,"baseSeverity":"MEDIUM","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"LOW","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","userInteraction":"ACTIVE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"LOW","vulnConfidentialityImpact":"NO…

cve_program_cvelist_v5cvss
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /containers/cna/metrics/0/cvssV4_0

CWE assertions

1 source assertion

{"cweId":"CWE-78","description":"CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')","lang":"en","type":"CWE"}

cve_program_cvelist_v5cwe
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /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_v5reference
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /containers/cna/references/0

{"tags":["product"],"url":"https://cgit.git.savannah.gnu.org/cgit/bison.git/"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /containers/cna/references/1

{"tags":["patch"],"url":"https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=3169c1e7a2c6acc4c59dfcf8b089896d6881925b"}

cve_program_cvelist_v5reference
urn:baitaphish:normalized-source-record:v2:9f862bb2b3be53b9aefe9e0ae4083c21be966d4561d81d2ab7ac304df999521a · sha256:9f508077b109df18… · /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.

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