Vulnerability-Lookup

GHSA-V898-XG3C-W4RJ

Vulnerability from github – Published: 2026-04-20 21:31 – Updated: 2026-04-21 21:31

Details

Calling the scanf family of functions with a %mc (malloc'd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.

Severity ?

9.8 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-5450"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-122",
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-20T21:16:36Z",
    "severity": "CRITICAL"
  },
  "details": "Calling the scanf family of functions with a %mc (malloc\u0027d character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.",
  "id": "GHSA-v898-xg3c-w4rj",
  "modified": "2026-04-21T21:31:22Z",
  "published": "2026-04-20T21:31:46Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-5450"
    },
    {
      "type": "WEB",
      "url": "https://inbox.sourceware.org/libc-announce/b11f0003-6ec1-4bd6-b9de-9e38a4efeca3@redhat.com/T/#u"
    },
    {
      "type": "WEB",
      "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-5450 (GCVE-0-2026-5450)

Vulnerability from cvelistv5 – Published: 2026-04-20 20:55 – Updated: 2026-04-21 19:49

Title

scanf %mc off-by-one heap buffer overflow

Summary

Severity ?

9.8 (Critical)


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

CWE

CWE-122 - Heap-based buffer overflow

Assigner

glibc

References

URL

Tags

	https://sourceware.org/bugzilla/show_bug.cgi?id=C…	issue-tracking
	https://inbox.sourceware.org/libc-announce/b11f00…	mailing-list

Impacted products

	Vendor	Product	Version
	The GNU C Library	glibc	Affected: 2.7 , < * (custom)

Date Public ?

2026-03-19 17:36

Credits

Rocket Ma

Show details on NVD website

JSON

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  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-5450",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-21T16:11:50.875542Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-21T19:49:53.221Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "glibc",
          "vendor": "The GNU C Library",
          "versions": [
            {
              "lessThan": "*",
              "status": "affected",
              "version": "2.7",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
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          "type": "finder",
          "value": "Rocket Ma"
        }
      ],
      "datePublic": "2026-03-19T17:36:00.000Z",
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          ],
          "value": "Calling the scanf family of functions with a %mc (malloc\u0027d character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow."
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      ],
      "impacts": [
        {
          "capecId": "CAPEC-100",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-100 Overflow Buffers"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
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              "description": "CWE-122 Heap-based buffer overflow",
              "lang": "en",
              "type": "CWE"
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      "providerMetadata": {
        "dateUpdated": "2026-04-20T20:55:41.170Z",
        "orgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
        "shortName": "glibc"
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      "references": [
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            "issue-tracking"
          ],
          "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=CVE-2026-5450"
        },
        {
          "tags": [
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          "url": "https://inbox.sourceware.org/libc-announce/b11f0003-6ec1-4bd6-b9de-9e38a4efeca3@redhat.com/T/#u"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "scanf %mc off-by-one heap buffer overflow",
      "x_generator": {
        "engine": "Vulnogram 1.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
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    "cveId": "CVE-2026-5450",
    "datePublished": "2026-04-20T20:55:41.170Z",
    "dateReserved": "2026-04-02T21:47:21.403Z",
    "dateUpdated": "2026-04-21T19:49:53.221Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

GHSA-V898-XG3C-W4RJ

CVE-2026-5450 (GCVE-0-2026-5450)

Tags

Sightings

Nomenclature