Vulnerability-Lookup

CVE-2026-56391 (GCVE-0-2026-56391)

Vulnerability from cvelistv5 – Published: 2026-07-24 07:44 – Updated: 2026-07-24 12:31 X_Open Source

Title

Out‑of‑bounds Read in GNU coreutils

Summary

GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

Severity

4.6 (Medium)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-24 12:31 UTC

CWE

CWE-125 - Out-of-bounds Read

Assigner

CERT-PL ENISA root

References

3 references

URL	Tags
https://cert.pl/en/posts/2026/07/CVE-2026-56391	third-party-advisory
https://git.savannah.gnu.org/cgit/coreutils.git/	product
https://git.savannah.gnu.org/cgit/coreutils.git/c…	patch

Impacted products

1 product

Vendor	Product	Version	CPE status
GNU	coreutils	Affected: 9.5 , ≤ 9.11 (custom)	guessed

Credits

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

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-56391

Vulnerability from fkie_nvd - Published: 2026-07-24 09:16 - Updated: 2026-08-26 13:52

Severity

6.1 (Medium) - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Summary

References

URL	Tags
cvd@cert.pl	https://cert.pl/en/posts/2026/07/CVE-2026-56391	Third Party Advisory
cvd@cert.pl	https://git.savannah.gnu.org/cgit/coreutils.git/	Product
cvd@cert.pl	https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371	Patch

Impacted products

	Vendor	Product	Version
	gnu	coreutils	*

JSON

To clipboard

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          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "ACTIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "LOW",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "cvd@cert.pl",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-56391",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-07-24T12:31:16.655541Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-07-24T09:16:25.003",
  "references": [
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Third Party Advisory"
      ],
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56391"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Product"
      ],
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git/"
    },
    {
      "source": "cvd@cert.pl",
      "tags": [
        "Patch"
      ],
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371"
    }
  ],
  "sourceIdentifier": "cvd@cert.pl",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "cvd@cert.pl",
      "type": "Secondary"
    }
  ]
}

GHSA-7XVJ-M9X7-QGXQ

Vulnerability from github – Published: 2026-07-24 09:32 – Updated: 2026-07-24 09:32

Details

When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure.

This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

Severity

4.6 (Medium)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-56391"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-125"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-24T09:16:25Z",
    "severity": "MODERATE"
  },
  "details": "GNU coreutils uniq is vulnerable to an out\u2011of\u2011bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. \nThis incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input.\n\nWhen running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure.\n\n\nThis issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.",
  "id": "GHSA-7xvj-m9x7-qgxq",
  "modified": "2026-07-24T09:32:16Z",
  "published": "2026-07-24T09:32:16Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56391"
    },
    {
      "type": "WEB",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56391"
    },
    {
      "type": "WEB",
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git"
    },
    {
      "type": "WEB",
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/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"
    }
  ]
}

OPENSUSE-SU-2026:11764-1

Vulnerability from csaf_opensuse - Published: 2026-09-12 00:00 - Updated: 2026-09-16 21:30

Summary

coreutils-9.11-5.1 on GA media

Severity

Moderate

Scope

2 vulnerabilities in this advisory, including CVE-2026-56391.

CVE-2026-56391

6.1 (Medium)


                
                  CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Recommended: 12 products

Open the full advisory

RHSA-2026:67886

Vulnerability from csaf_opensuse - Published: 2026-09-16 00:00 - Updated: 2026-09-16 18:52

Summary

security update for coreutils

Severity

Moderate

Scope

2 vulnerabilities in this advisory, including CVE-2026-56391.

CVE-2026-56391

6.1 (Medium)


                
                  CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Recommended: 3 products

Open the full advisory

RHSA-2026:46515

Vulnerability from csaf_redhat - Published: 2026-07-27 11:04 - Updated: 2026-09-16 10:35

Summary

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Severity

Moderate

Scope

1 vulnerability in this advisory, including CVE-2026-56391.

CVE-2026-56391

A flaw was found in GNU coreutils uniq. When processing specially crafted multibyte input with the --check-chars option, an attacker can trigger an out-of-bounds read. This vulnerability can lead to a denial of service (DoS) due to an application crash and potentially expose sensitive information from adjacent memory.

6.1 (Medium)


                
                  CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

Fixed: 3 products

https://access.redhat.com/errata/RHSA-2026:46515

Open the full advisory

ubuntu-cve-2026-56391

Vulnerability from osv_ubuntu

Published

2026-07-24 09:16

Modified

2026-08-31 14:24

Summary

Details

Severity

4.6 (Medium)


                    
                      CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N

6.1 (Medium)


                    
                      CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-56391	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-56391	REPORT
	https://www.openwall.com/lists/oss-security/2026/…	REPORT
	https://cert.pl/en/posts/2026/07/CVE-2026-56391	REPORT
	https://ubuntu.com/security/notices/USN-8697-1	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "gnu-coreutils",
            "binary_version": "9.7-3ubuntu2.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@9.7-3ubuntu2.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9.7-3ubuntu2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.5-1ubuntu4",
        "9.7-3ubuntu1",
        "9.7-3ubuntu2"
      ]
    }
  ],
  "aliases": [],
  "details": "GNU coreutils uniq is vulnerable to an out\u2011of\u2011bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.",
  "id": "UBUNTU-CVE-2026-56391",
  "modified": "2026-08-31T14:24:07Z",
  "published": "2026-07-24T09:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-56391"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-56391"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2026/07/25/2"
    },
    {
      "type": "REPORT",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56391"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8697-1"
    }
  ],
  "related": [
    "USN-8697-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-56391"
  ]
}

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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-56391 (GCVE-0-2026-56391)

FKIE_CVE-2026-56391

GHSA-7XVJ-M9X7-QGXQ

OPENSUSE-SU-2026:11764-1

RHSA-2026:67886

RHSA-2026:46515

ubuntu-cve-2026-56391

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature

Related by attack behaviour