Vulnerability-Lookup

FKIE_CVE-2026-49421

Vulnerability from fkie_nvd - Published: 2026-08-19 06:17 - Updated: 2026-09-01 20:20

Severity

7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Summary

The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup. The flag was silently dropped, so path resolution was not actually restricted. A process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory. A caller relying on this flag for path containment may delete files outside the intended directory tree.

References

	URL	Tags
	secteam@freebsd.org	https://security.freebsd.org/advisories/FreeBSD-SA-26:42.unlinkat.asc	Vendor Advisory

Impacted products

Vendor	Product	Version
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.3
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	14.4
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.0
freebsd	freebsd	15.1
freebsd	freebsd	15.1
freebsd	freebsd	15.1

JSON

To clipboard

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  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup.  The flag was silently dropped, so path resolution was not actually restricted.\n\nA process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory.  A caller relying on this flag for path containment may delete files outside the intended directory tree."
    }
  ],
  "id": "CVE-2026-49421",
  "lastModified": "2026-09-01T20:20:06.177",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
          "version": "3.1"
        },
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        "impactScore": 5.2,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
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        "ssvcData": {
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          "options": [
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            {
              "automatable": "no"
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            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-26T17:44:11.280156Z",
          "version": "2.0.3"
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  "published": "2026-08-19T06:17:41.160",
  "references": [
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      "source": "secteam@freebsd.org",
      "tags": [
        "Vendor Advisory"
      ],
      "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:42.unlinkat.asc"
    }
  ],
  "sourceIdentifier": "secteam@freebsd.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "description": [
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          "lang": "en",
          "value": "CWE-273"
        }
      ],
      "source": "secteam@freebsd.org",
      "type": "Secondary"
    }
  ]
}

CVE-2026-49421 (GCVE-0-2026-49421)

Vulnerability from cvelistv5 – Published: 2026-08-19 05:25 – Updated: 2026-08-26 17:44

Title

unlinkat(2) ignores AT_RESOLVE_BENEATH flag

Summary

Severity

7.1 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 17:44 UTC

CWE

CWE-273 - Improper Check for Dropped Privileges

Assigner

freebsd CNA under the mitre root

CNA scorecard D 60/100 over 69 records in the last 180 days details

References

1 reference

URL	Tags
https://security.freebsd.org/advisories/FreeBSD-S…	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
FreeBSD	FreeBSD	Affected: 15.1-RELEASE , < p1 (release) Affected: 15.0-RELEASE , < p11 (release) Affected: 14.4-RELEASE , < p7 (release) Affected: 14.3-RELEASE , < p16 (release)

Date Public

2026-06-30 20:00

Credits

Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.1,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "NONE",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-49421",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-26T17:44:11.280156Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-26T17:44:13.985Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "libalias"
          ],
          "product": "FreeBSD",
          "vendor": "FreeBSD",
          "versions": [
            {
              "lessThan": "p1",
              "status": "affected",
              "version": "15.1-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p11",
              "status": "affected",
              "version": "15.0-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p7",
              "status": "affected",
              "version": "14.4-RELEASE",
              "versionType": "release"
            },
            {
              "lessThan": "p16",
              "status": "affected",
              "version": "14.3-RELEASE",
              "versionType": "release"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Yuxiang Yang, Yizhou Zhao, Ao Wang, Xuewei Feng, Qi Li, and Ke Xu from Tsinghua University using GLM-5.1 from Z.ai"
        }
      ],
      "datePublic": "2026-06-30T20:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup.  The flag was silently dropped, so path resolution was not actually restricted.\n\nA process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory.  A caller relying on this flag for path containment may delete files outside the intended directory tree."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-273",
              "description": "CWE-273: Improper Check for Dropped Privileges",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T05:25:43.003Z",
        "orgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
        "shortName": "freebsd"
      },
      "references": [
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:42.unlinkat.asc"
        }
      ],
      "title": "unlinkat(2) ignores AT_RESOLVE_BENEATH flag",
      "x_generator": {
        "engine": "cvelib 1.8.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "63664ac6-956c-4cba-a5d0-f46076e16109",
    "assignerShortName": "freebsd",
    "cveId": "CVE-2026-49421",
    "datePublished": "2026-08-19T05:25:43.003Z",
    "dateReserved": "2026-05-29T20:24:28.616Z",
    "dateUpdated": "2026-08-26T17:44:13.985Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

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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

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