Vulnerability-Lookup

GHSA-4F5J-WQJR-HX49

Vulnerability from github – Published: 2026-08-03 18:30 – Updated: 2026-08-03 18:30

Details

A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.

Severity

4.4 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-18508"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-59"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-03T16:16:28Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.",
  "id": "GHSA-4f5j-wqjr-hx49",
  "modified": "2026-08-03T18:30:45Z",
  "published": "2026-08-03T18:30:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18508"
    },
    {
      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-18508"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2509843"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-18508 (GCVE-0-2026-18508)

Vulnerability from cvelistv5 – Published: 2026-08-03 14:51 – Updated: 2026-08-03 16:06

Title

Tar: tar: --one-top-level hardlink targets not confined to top-level directory enabling arbitrary file overwrite

Summary

Severity

4.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Assigner

redhat

References

2 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-18508	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2509843	issue-trackingx_refsource_REDHAT

Impacted products

7 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 6	cpe:/o:redhat:enterprise_linux:6
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat Hardened Images	cpe:/a:redhat:hummingbird:1
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4

Date Public

2026-07-31 00:00

Credits

This issue was discovered by Pavel Cahyna (Red Hat).

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JSON

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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.

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GHSA-4F5J-WQJR-HX49

CVE-2026-18508 (GCVE-0-2026-18508)

Tags

Sightings

Nomenclature