CVE-2026-56390

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Source
https://cve.org/CVERecord?id=CVE-2026-56390
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56390.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-56390
Downstream
AZL (1)
DEBIAN (1)
ECHO (1)
JLSEC (1)
OESA (4)
UBUNTU (1)
Published
2026-07-29T09:40:03Z
Modified
2026-10-25T02:49:07Z
Severity
  • 4.6 (Medium) CVSS_V4 - 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 CVSS Calculator
Summary
Arbitrary Output Location Change in GNU Bison
Details

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, and fixed the issue in commit 8d101c19d4d9aaedf83a448c925513742d4efcf0. 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.

Database specific 
{
    "cna_assigner":  "CERT-PL",
    "cwe_ids":  [
        "CWE-73"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56390.json",
    "unresolved_ranges":  [
        {
            "extracted_events":  [
                {
                    "range":  [
                        {
                            "introduced":  "3.8.2"
                        },
                        {
                            "last_affected":  "3.8.2"
                        }
                    ],
                    "source":  "AFFECTED_FIELD",
                    "strategy":  "StandaloneSingleVersion"
                }
            ]
        }
    ]
}
References

Affected packages

Git / cgit.git.savannah.gnu.org/cgit/bison.git

Affected ranges

Type
GIT
Repo
https://cgit.git.savannah.gnu.org/cgit/bison.git
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
8d101c19d4d9aaedf83a448c925513742d4efcf0
Database specific
Show details 
{
    "extracted_events":  [
        {
            "range":  [
                {
                    "fixed":  "8d101c19d4d9aaedf83a448c925513742d4efcf0"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-56390.json"