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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.
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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": [
            {
              "lessThan": "a99a617701186dc68c7b330d35fc2253f48e2ab2",
              "status": "affected",
              "version": "8230fd8217b7ea76f838ae88e4a5a8e54f37099f",
              "versionType": "git"
            },
            {
              "lessThan": "5492799ec5d27be3bd454dcaf046bc7054f637ae",
              "status": "affected",
              "version": "8230fd8217b7ea76f838ae88e4a5a8e54f37099f",
              "versionType": "git"
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              "status": "affected",
              "version": "8230fd8217b7ea76f838ae88e4a5a8e54f37099f",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "8230fd8217b7ea76f838ae88e4a5a8e54f37099f",
              "versionType": "git"
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          ]
        },
        {
          "defaultStatus": "affected",
          "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"
      }
    }
  },
  "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": "2026-09-05",
      "epss": "0.00622",
      "percentile": "0.47291"
    },
    "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\":{\"id\":\"CVE-2026-72373\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:10.777\",\"lastModified\":\"2026-08-17T06:18:41.597\",\"vulnStatus\":\"Received\",\"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).\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/afs/callback.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"8230fd8217b7ea76f838ae88e4a5a8e54f37099f\",\"lessThan\":\"a99a617701186dc68c7b330d35fc2253f48e2ab2\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8230fd8217b7ea76f838ae88e4a5a8e54f37099f\",\"lessThan\":\"5492799ec5d27be3bd454dcaf046bc7054f637ae\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8230fd8217b7ea76f838ae88e4a5a8e54f37099f\",\"lessThan\":\"e3e59ff22a0de01ed0cf3a3e25558811abc3b70a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"8230fd8217b7ea76f838ae88e4a5a8e54f37099f\",\"lessThan\":\"794a01110390c1b76f59ece773fb0fbfd89c6f5c\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/afs/callback.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.8\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.8\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/5492799ec5d27be3bd454dcaf046bc7054f637ae\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/794a01110390c1b76f59ece773fb0fbfd89c6f5c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a99a617701186dc68c7b330d35fc2253f48e2ab2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e3e59ff22a0de01ed0cf3a3e25558811abc3b70a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "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"
    }
  }
}



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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

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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.