Vulnerability-Lookup

GHSA-854R-XW42-GJ8X

Vulnerability from github – Published: 2026-10-18 18:32 – Updated: 2026-10-18 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT

FGUs don't actually require hardware support, so don't gate fgt trap config insertion on FGT. This is the only action required to allow FGUs always, as kvm_calculate_traps() already computes the FGU bits with or without FEAT_FGT.

This also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1 without FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the course-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(), which expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF will be injected without needing the specific handler.

[oliver: Take Wei-Lin's suggested changelog]

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-98713"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:24Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT\n\nFGUs don\u0027t actually require hardware support, so don\u0027t gate fgt trap\nconfig insertion on FGT. This is the only action required to allow FGUs\nalways, as kvm_calculate_traps() already computes the FGU bits with or\nwithout FEAT_FGT.\n\nThis also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1\nwithout FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the\ncourse-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(),\nwhich expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF\nwill be injected without needing the specific handler.\n\n[oliver: Take Wei-Lin\u0027s suggested changelog]",
  "id": "GHSA-854r-xw42-gj8x",
  "modified": "2026-10-18T18:32:00Z",
  "published": "2026-10-18T18:32:00Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98713"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2f4a15c52a552c5244ec27f4ca8bda855594f918"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/af3300b3a6bace925a496f3520e171c07b999c72"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98713 (GCVE-0-2026-98713)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:46 – Updated: 2026-10-19 09:24

Title

KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT FGUs don't actually require hardware support, so don't gate fgt trap config insertion on FGT. This is the only action required to allow FGUs always, as kvm_calculate_traps() already computes the FGU bits with or without FEAT_FGT. This also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1 without FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the course-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(), which expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF will be injected without needing the specific handler. [oliver: Take Wei-Lin's suggested changelog]

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6971 records in the last 180 days details

References

4 references

URL	Tags
https://git.kernel.org/stable/c/2f4a15c52a552c524…
https://git.kernel.org/stable/c/1113374a17d7f7d16…
https://git.kernel.org/stable/c/af3300b3a6bace925…
https://git.kernel.org/stable/c/4bdd2b3a708c1feb7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f , < 2f4a15c52a552c5244ec27f4ca8bda855594f918 (git) Affected: f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f , < 1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087 (git) Affected: f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f , < af3300b3a6bace925a496f3520e171c07b999c72 (git) Affected: f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f , < 4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07 (git)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 6.12.113 , ≤ 6.12.* (semver) Unaffected: 6.18.56 , ≤ 6.18.* (semver) Unaffected: 7.2.10 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/emulate-nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "2f4a15c52a552c5244ec27f4ca8bda855594f918",
              "status": "affected",
              "version": "f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f",
              "versionType": "git"
            },
            {
              "lessThan": "1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087",
              "status": "affected",
              "version": "f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f",
              "versionType": "git"
            },
            {
              "lessThan": "af3300b3a6bace925a496f3520e171c07b999c72",
              "status": "affected",
              "version": "f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f",
              "versionType": "git"
            },
            {
              "lessThan": "4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07",
              "status": "affected",
              "version": "f5a5a406b4b8bb6c1fc7a1e92a872bd86061a53f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/emulate-nested.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.113",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.56",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.10",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT\n\nFGUs don\u0027t actually require hardware support, so don\u0027t gate fgt trap\nconfig insertion on FGT. This is the only action required to allow FGUs\nalways, as kvm_calculate_traps() already computes the FGU bits with or\nwithout FEAT_FGT.\n\nThis also fixes a spurious WARN when a TLBI OS is run on a guest in vEL1\nwithout FEAT_TLBIOS on non FEAT_FGT hardware. In this configuration the\ncourse-grained HCR_EL2.TTLBOS trap reaches the handler handle_tlbi_el1(),\nwhich expects an EL1 TLBI only from vEL2. With FGUs enabled the UNDEF\nwill be injected without needing the specific handler.\n\n[oliver: Take Wei-Lin\u0027s suggested changelog]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:24:24.367Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/2f4a15c52a552c5244ec27f4ca8bda855594f918"
        },
        {
          "url": "https://git.kernel.org/stable/c/1113374a17d7f7d16b02ee0bbd9b1e7a60cbb087"
        },
        {
          "url": "https://git.kernel.org/stable/c/af3300b3a6bace925a496f3520e171c07b999c72"
        },
        {
          "url": "https://git.kernel.org/stable/c/4bdd2b3a708c1feb701cb8b62feb8ad2fd77bb07"
        }
      ],
      "title": "KVM: arm64: Apply the fine-grained UNDEFs without FEAT_FGT",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98713",
    "datePublished": "2026-10-18T15:46:45.902Z",
    "dateReserved": "2026-09-25T10:25:14.365Z",
    "dateUpdated": "2026-10-19T09:24:24.367Z",
    "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

Publication & reservation Sightings KEV catalogs Other timestamps

Loading timeline…

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