Detections
Analytics
Linux Distros Unpatched Vulnerability : CVE-2026-56390
medium Nessus Plugin ID 330727
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Synopsis
The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.Description
The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.- GNU Bison improperly handles grammardefined output paths. Grammar directives such as %output and %header allow specifying file paths, which are accepted without restriction and override callersupplied 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. (CVE-2026-56390)
Note that Nessus relies on the presence of the package as reported by the vendor.
Solution
There is no known solution at this time.See Also
https://access.redhat.com/security/cve/cve-2026-56390
Plugin Details
Severity: Medium
ID: 330727
File Name: unpatched_CVE_2026_56390.nasl
Version: 1.3
Type: Local
Agent: unix
Family: Misc.
Published: 7/29/2026
Updated: 7/30/2026
Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 5
Percentile: 93.91
CVSS v2
Risk Factor: Medium
Base Score: 5
Temporal Score: 4.3
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:P/A:N
CVSS Score Source: CVE-2026-56390
CVSS v3
Risk Factor: Medium
Base Score: 6.2
Temporal Score: 5.7
Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C
CVSS v4
Risk Factor: Medium
Base Score: 4.6
Threat Score: 1
Threat Vector: CVSS:4.0/E:U
Vector: 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
Vulnerability Information
CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:centos:centos:7, cpe:/o:centos:centos:8, cpe:/o:debian:debian_linux:11.0, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, cpe:/o:debian:debian_linux:14.0, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:canonical:ubuntu_linux:bison, p-cpe:/a:centos:centos:bison-devel, p-cpe:/a:centos:centos:bison-runtime, p-cpe:/a:centos:centos:bison, p-cpe:/a:debian:debian_linux:bison, p-cpe:/a:redhat:enterprise_linux:bison-devel, p-cpe:/a:redhat:enterprise_linux:bison-runtime, p-cpe:/a:redhat:enterprise_linux:bison
Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier
Exploit Ease: No known exploits are available
Vulnerability Publication Date: 7/29/2026
Reference Information
CVE: CVE-2026-56390