CVE-2026-72373 (GCVE-0-2026-72373)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43
VLAI
Title
afs: Fix missing NULL pointer check in afs_break_some_callbacks()
Summary
In the Linux kernel, the following vulnerability has been resolved: afs: Fix missing NULL pointer check in afs_break_some_callbacks() Fix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu() returned NULL (e.g. the specified volume is unknown).
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 8230fd8217b7ea76f838ae88e4a5a8e54f37099f , < a99a617701186dc68c7b330d35fc2253f48e2ab2 (git)
Affected: 8230fd8217b7ea76f838ae88e4a5a8e54f37099f , < 5492799ec5d27be3bd454dcaf046bc7054f637ae (git)
Affected: 8230fd8217b7ea76f838ae88e4a5a8e54f37099f , < e3e59ff22a0de01ed0cf3a3e25558811abc3b70a (git)
Affected: 8230fd8217b7ea76f838ae88e4a5a8e54f37099f , < 794a01110390c1b76f59ece773fb0fbfd89c6f5c (git)
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Linux Linux Affected: 5.8
Unaffected: 0 , < 5.8 (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/afs/callback.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "8230fd8217b7ea76f838ae88e4a5a8e54f37099f",
              "versionType": "git"
            },
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              "versionType": "git"
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        {
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          "product": "Linux",
          "programFiles": [
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix missing NULL pointer check in afs_break_some_callbacks()\n\nFix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu()\nreturned NULL (e.g. the specified volume is unknown)."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is reached when an AFS fileserver sends a CB.CallBack/YFSCB.CallBack RPC over RxRPC to the kernel cache-manager listener; processing flows through SRXAFSCB_CallBack() to afs_break_some_callbacks() with no local syscall required.\nAC:L - A malicious or compromised fileserver that already has an encrypted RxRPC callback channel can reliably send a volume-level callback break (vnode=0, unique=0) for an arbitrary unknown volume ID, deterministically driving afs_lookup_volume_rcu() to return NULL and crash.\nPR:N - Exploitation requires no privileges on the victim host; a remote peer authenticated as a known AFS fileserver can deliver the crafted callback break without the attacker holding local user, capability, or namespace rights on the client.\nUI:N - Once AFS is mounted and a server callback connection exists, triggering the NULL dereference needs no further end-user action\u2014the fileserver can unilaterally send the malformed callback notification at any time.\nS:U - Impact is confined to kernel memory in the AFS client callback path (NULL dereference and possible oops/panic); it does not cross a VM, container, or IOMMU security boundary to affect a different authority.\nC:N - The failure mode is a NULL pointer dereference on volume-\u003eservers in afs_break_volume_callback(); there is no out-of-bounds access, use-after-free, or other memory corruption that could disclose kernel data.\nI:N - The bug causes an immediate invalid read through a NULL volume pointer and does not provide controlled writes, metadata corruption, or a path to arbitrary code execution beyond crashing the kernel.\nA:H - Hitting afs_break_volume_callback() with a NULL volume dereferences volume-\u003eservers under RCU, provoking a kernel oops or panic and denying availability to the entire system until reboot."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:43:26.499Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a99a617701186dc68c7b330d35fc2253f48e2ab2"
        },
        {
          "url": "https://git.kernel.org/stable/c/5492799ec5d27be3bd454dcaf046bc7054f637ae"
        },
        {
          "url": "https://git.kernel.org/stable/c/e3e59ff22a0de01ed0cf3a3e25558811abc3b70a"
        },
        {
          "url": "https://git.kernel.org/stable/c/794a01110390c1b76f59ece773fb0fbfd89c6f5c"
        }
      ],
      "title": "afs: Fix missing NULL pointer check in afs_break_some_callbacks()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72373",
    "datePublished": "2026-08-15T05:56:08.564Z",
    "dateReserved": "2026-08-09T03:40:39.922Z",
    "dateUpdated": "2026-08-17T05:43:26.499Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72373",
      "date": "2026-09-21",
      "epss": "0.00622",
      "percentile": "0.48132"
    },
    "microsoft_vex": {
      "current_release_date": "2026-08-23T14:44:52.000Z",
      "cve": "CVE-2026-72373",
      "id": "msrc_CVE-2026-72373",
      "initial_release_date": "2026-08-23T14:44:52.000Z",
      "product_status:known_not_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "afs: Fix missing NULL pointer check in afs_break_some_callbacks()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-72373.json",
      "version": "1"
    },
    "nvd": {
      "cve": {
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                "product": "Linux",
                "programFiles": [
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                ],
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                "vendor": "Linux",
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                "vendor": "Linux",
                "versions": [
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                    "version": "0",
                    "versionType": "semver"
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                    "versionType": "semver"
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                    "version": "6.18.40",
                    "versionType": "semver"
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                    "status": "unaffected",
                    "version": "7.1.5",
                    "versionType": "semver"
                  },
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                    "version": "7.2",
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              }
            ],
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix missing NULL pointer check in afs_break_some_callbacks()\n\nFix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu()\nreturned NULL (e.g. the specified volume is unknown)."
          }
        ],
        "id": "CVE-2026-72373",
        "lastModified": "2026-08-17T06:18:41.597",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-08-15T06:22:10.777",
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        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-17T13:45:22+00:00",
      "cve": "CVE-2026-72373",
      "id": "CVE-2026-72373",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: afs: Fix missing NULL pointer check in afs_break_some_callbacks()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72373.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-07T16:23:18Z",
      "cve": "CVE-2026-72373",
      "id": "CVE-2026-72373",
      "initial_release_date": "2026-08-27T16:53:16Z",
      "product_status:known_not_affected": "362",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72373",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72373.json",
      "version": "4"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.


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.