Vulnerability-Lookup

CVE-2026-56389 (GCVE-0-2026-56389)

Vulnerability from cvelistv5 – Published: 2026-07-29 09:39 – Updated: 2026-07-29 12:21 X_Open Source

Title

Arbitrary Command Execution in GNU Bison

Summary

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.

Severity

6.8 (Medium)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Assigner

CERT-PL

References

3 references

URL	Tags
https://cert.pl/en/posts/2026/07/CVE-2026-56389	third-party-advisory
https://cgit.git.savannah.gnu.org/cgit/bison.git/	product
https://cgit.git.savannah.gnu.org/cgit/bison.git/…	patch

Impacted products

1 product

Vendor	Product	Version
GNU	Bison	Affected: 3.8.2 (semver)

Credits

Michał Majchrowicz (AFINE Team) Marcin Wyczechowski (AFINE Team)

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-56389

Vulnerability from fkie_nvd - Published: 2026-07-29 11:16 - Updated: 2026-07-30 16:28

Severity

6.8 (Medium) - 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

Summary

References

	URL	Tags
	cvd@cert.pl	https://cert.pl/en/posts/2026/07/CVE-2026-56389
	cvd@cert.pl	https://cgit.git.savannah.gnu.org/cgit/bison.git/
	cvd@cert.pl	https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=3169c1e7a2c6acc4c59dfcf8b089896d6881925b

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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    }
  ],
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GHSA-735P-4PRJ-F62V

Vulnerability from github – Published: 2026-07-29 12:31 – Updated: 2026-07-29 12:31

Details

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.

Severity

6.8 (Medium)


                  
                    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

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-56389"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-78"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-29T11:16:49Z",
    "severity": "MODERATE"
  },
  "details": "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\u2011to\u2011HTML transformation step via %define tool.xsltproc, which is accepted without restriction and passed directly to execvp().\n \nWhen running bison --html on a attacker-provided grammar, this behavior allows execution of an arbitrary program with the privileges of the Bison process.\n\n\nMaintainers 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\u00a0and confirmed as vulnerable, other versions were not tested but might also be vulnerable.",
  "id": "GHSA-735p-4prj-f62v",
  "modified": "2026-07-29T12:31:23Z",
  "published": "2026-07-29T12:31:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56389"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56389"
    },
    {
      "type": "WEB",
      "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git"
    },
    {
      "type": "WEB",
      "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=3169c1e7a2c6acc4c59dfcf8b089896d6881925b"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ]
}

ubuntu-cve-2026-56389

Vulnerability from osv_ubuntu

Published

2026-07-29 11:16

Modified

2026-08-06 00:20

Summary

Details

Severity

6.8 (Medium)


                    
                      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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-56389	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-56389	REPORT
	https://cert.pl/en/posts/2026/07/CVE-2026-56389	REPORT
	https://cgit.git.savannah.gnu.org/cgit/bison.git/…	REPORT
	https://cgit.git.savannah.gnu.org/cgit/bison.git/	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.0.4.dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.0.4.dfsg-1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.0.2.dfsg-2",
        "2:3.0.4.dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.0.4.dfsg-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.0.4.dfsg-1build1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.0.4.dfsg-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.5.1+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.5.1+dfsg-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.4.1+dfsg-4",
        "2:3.4.2+dfsg-1",
        "2:3.5.1+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.8.2+dfsg-1build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.8.2+dfsg-1build1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.7.6+dfsg-1build1",
        "2:3.8.2+dfsg-1",
        "2:3.8.2+dfsg-1build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.8.2+dfsg-1build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.8.2+dfsg-1build2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.8.2+dfsg-1build1",
        "2:3.8.2+dfsg-1build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "bison",
            "binary_version": "2:3.8.2+dfsg-1build4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "bison",
        "purl": "pkg:deb/ubuntu/bison@2:3.8.2+dfsg-1build4?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:3.8.2+dfsg-1build3",
        "2:3.8.2+dfsg-1build4"
      ]
    }
  ],
  "aliases": [],
  "details": "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\u2011to\u2011HTML 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\u00a0and confirmed as vulnerable, other versions were not tested but might also be vulnerable.",
  "id": "UBUNTU-CVE-2026-56389",
  "modified": "2026-08-06T00:20:55Z",
  "published": "2026-07-29T11:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-56389"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-56389"
    },
    {
      "type": "REPORT",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56389"
    },
    {
      "type": "REPORT",
      "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git/commit/?id=3169c1e7a2c6acc4c59dfcf8b089896d6881925b"
    },
    {
      "type": "REPORT",
      "url": "https://cgit.git.savannah.gnu.org/cgit/bison.git/"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-56389"
  ]
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-56389 (GCVE-0-2026-56389)

FKIE_CVE-2026-56389

GHSA-735P-4PRJ-F62V

ubuntu-cve-2026-56389

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature