CVE-2026-97583 (GCVE-0-2026-97583)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:22 – Updated: 2026-09-25 14:41
VLAI
Title
afs: Clear stale peer app data after address list changes
Summary
In the Linux kernel, the following vulnerability has been resolved: afs: Clear stale peer app data after address list changes afs_fs_probe_fileserver() fetches the current endpoint state under server->fs_lock, but leaves old_alist as NULL. Consequently, afs_set_peer_appdata() treats every address list replacement as initial setup and only binds the new peers; it never unbinds peers removed from the old list. An address refresh can therefore proceed as follows. CPU 0 replaces server S's list and drops Pold without clearing Pold->app_data. The server destroyer then clears only S's current peers and lets S reach its RCU callback. After the callback frees S, CPU 1 handles a callback through an RxRPC connection that still pins Pold, reads Pold->app_data, and calls afs_use_server() on the freed object. KASAN reported: BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0 Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74 Call Trace: afs_find_server+0x3c/0xa0 afs_rx_new_call+0x15c/0x390 rxrpc_new_incoming_call+0x97c/0x1730 rxrpc_input_packet.constprop.0+0xd03/0xec0 rxrpc_io_thread+0x967/0x1640 Allocated by task 93: afs_lookup_server+0x1a7/0x14c0 afs_alloc_server_list+0x43f/0xb60 afs_create_volume+0x923/0x1490 afs_get_tree+0x1c6/0x10a0 Freed by task 0: kfree+0x131/0x3c0 rcu_core+0x50a/0x1850 Last potentially related work creation: __call_rcu_common.constprop.0+0x71/0xa10 afs_put_server+0x213/0x2b0 Preserve old->addresses for the peer app-data update so that removed peers are cleared before the endpoint state is replaced. Also advance both cursors when the old and new lists share a peer; activating the old/new comparison without this would otherwise loop forever on the shared entry.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 39ba6af83a7f9dee3e6a7916f41a48bcbda54eba , < 3afb988fd0411707bdafb9b321086fff0da28aae (git)
Affected: 40e8b52fe8c8ab6920ea5f59c5469b6918cce624 , < c7f77a11a1e719192c7262aad38a3919aec62c21 (git)
Affected: 40e8b52fe8c8ab6920ea5f59c5469b6918cce624 , < 7f7f5589d048821dea316cbac9b37d27eaf7530e (git)
Affected: 40e8b52fe8c8ab6920ea5f59c5469b6918cce624 , < ba0623fc19a424f4745394c499f9f28a8d88d397 (git)
Affected: 6.12.101 , < 6.12.111 (semver)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/afs/addr_list.c",
            "fs/afs/fs_probe.c"
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              "version": "7.2.7",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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          "nodes": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.12.101",
                  "vulnerable": true
                },
                {
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Clear stale peer app data after address list changes\n\nafs_fs_probe_fileserver() fetches the current endpoint state under\nserver-\u003efs_lock, but leaves old_alist as NULL.  Consequently,\nafs_set_peer_appdata() treats every address list replacement as initial\nsetup and only binds the new peers; it never unbinds peers removed from\nthe old list.\n\nAn address refresh can therefore proceed as follows.  CPU 0 replaces\nserver S\u0027s list and drops Pold without clearing Pold-\u003eapp_data.  The\nserver destroyer then clears only S\u0027s current peers and lets S reach its\nRCU callback.  After the callback frees S, CPU 1 handles a callback\nthrough an RxRPC connection that still pins Pold, reads Pold-\u003eapp_data,\nand calls afs_use_server() on the freed object.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0\n  Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74\n  Call Trace:\n   afs_find_server+0x3c/0xa0\n   afs_rx_new_call+0x15c/0x390\n   rxrpc_new_incoming_call+0x97c/0x1730\n   rxrpc_input_packet.constprop.0+0xd03/0xec0\n   rxrpc_io_thread+0x967/0x1640\n  Allocated by task 93:\n   afs_lookup_server+0x1a7/0x14c0\n   afs_alloc_server_list+0x43f/0xb60\n   afs_create_volume+0x923/0x1490\n   afs_get_tree+0x1c6/0x10a0\n  Freed by task 0:\n   kfree+0x131/0x3c0\n   rcu_core+0x50a/0x1850\n  Last potentially related work creation:\n   __call_rcu_common.constprop.0+0x71/0xa10\n   afs_put_server+0x213/0x2b0\n\nPreserve old-\u003eaddresses for the peer app-data update so that removed\npeers are cleared before the endpoint state is replaced.  Also advance\nboth cursors when the old and new lists share a peer; activating the\nold/new comparison without this would otherwise loop forever on the\nshared entry."
        }
      ],
      "metrics": [
        {
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            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:N - A remote cell operator supplies the changed fileserver address list in the VL address-lookup reply (afs_vl_lookup_addrs -\u003e afs_fs_probe_fileserver). A later incoming RxRPC call over UDP from a dropped peer reaches afs_rx_new_call -\u003e afs_find_server, which dereferences the freed server through the stale peer app_data.\nAC:H - Triggering needs a specific order of events: the client refreshes the server\u0027s address list and gets a new version, then the server record goes unused and is freed by afs_server_destroyer after the GC delay, while an RxRPC connection still holds the old peer. Only then does a new incoming call hit it. The refresh and teardown timing follow the client\u0027s own activity, not the attacker\u0027s.\nPR:N - The VL reply and the incoming cache-manager call that reaches afs_rx_new_call/afs_find_server are handled before any server identity check. The attacker needs no account on the victim host.\nUI:R - The victim must have mounted, or be actively using, a volume from the attacker\u0027s AFS cell so that afs_lookup_server and afs_update_server_record run against the attacker\u0027s VL server. AFS mounts are not user-namespace mountable.\nS:U - The use-after-free happens in the kernel AFS client\u0027s afs_server object and stays within the kernel\u0027s own security authority. No VM, sandbox or IOMMU boundary is crossed.\nC:H - afs_use_server() works on a freed kmalloc\u0027d afs_server reached through the stale peer app_data. If that slab is reclaimed, fields the attacker controls are read as server state, including pointers, which can leak kernel memory.\nI:H - afs_use_server() increments the active counter, and the call path then takes references and queues work on the freed afs_server. Writing into a reallocated object gives a memory-corruption primitive that could be used to hijack control flow.\nA:H - A slab use-after-free in the krxrpcio I/O thread (see the KASAN report in the commit) can oops or panic the kernel and bring down all AFS and RxRPC service on the host."
            }
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "title": "afs: Clear stale peer app data after address list changes",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97583",
    "datePublished": "2026-09-25T10:22:03.666Z",
    "dateReserved": "2026-09-24T16:01:01.156Z",
    "dateUpdated": "2026-09-25T14:41:24.604Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
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      "date": "2026-09-29",
      "epss": "0.00408",
      "percentile": "0.32484"
    },
    "nvd": {
      "cve": {
        "affected": [
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                  "fs/afs/fs_probe.c"
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                "vendor": "Linux",
                "versions": [
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                    "version": "7.3-rc3",
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Clear stale peer app data after address list changes\n\nafs_fs_probe_fileserver() fetches the current endpoint state under\nserver-\u003efs_lock, but leaves old_alist as NULL.  Consequently,\nafs_set_peer_appdata() treats every address list replacement as initial\nsetup and only binds the new peers; it never unbinds peers removed from\nthe old list.\n\nAn address refresh can therefore proceed as follows.  CPU 0 replaces\nserver S\u0027s list and drops Pold without clearing Pold-\u003eapp_data.  The\nserver destroyer then clears only S\u0027s current peers and lets S reach its\nRCU callback.  After the callback frees S, CPU 1 handles a callback\nthrough an RxRPC connection that still pins Pold, reads Pold-\u003eapp_data,\nand calls afs_use_server() on the freed object.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in afs_find_server+0x3c/0xa0\n  Read of size 4 at addr ffff8881013e1af0 by task krxrpcio/7001/74\n  Call Trace:\n   afs_find_server+0x3c/0xa0\n   afs_rx_new_call+0x15c/0x390\n   rxrpc_new_incoming_call+0x97c/0x1730\n   rxrpc_input_packet.constprop.0+0xd03/0xec0\n   rxrpc_io_thread+0x967/0x1640\n  Allocated by task 93:\n   afs_lookup_server+0x1a7/0x14c0\n   afs_alloc_server_list+0x43f/0xb60\n   afs_create_volume+0x923/0x1490\n   afs_get_tree+0x1c6/0x10a0\n  Freed by task 0:\n   kfree+0x131/0x3c0\n   rcu_core+0x50a/0x1850\n  Last potentially related work creation:\n   __call_rcu_common.constprop.0+0x71/0xa10\n   afs_put_server+0x213/0x2b0\n\nPreserve old-\u003eaddresses for the peer app-data update so that removed\npeers are cleared before the endpoint state is replaced.  Also advance\nboth cursors when the old and new lists share a peer; activating the\nold/new comparison without this would otherwise loop forever on the\nshared entry."
          }
        ],
        "id": "CVE-2026-97583",
        "lastModified": "2026-09-25T15:18:00.290",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "REQUIRED",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-25T11:17:09.127",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/3afb988fd0411707bdafb9b321086fff0da28aae"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/7f7f5589d048821dea316cbac9b37d27eaf7530e"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ba0623fc19a424f4745394c499f9f28a8d88d397"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/c7f77a11a1e719192c7262aad38a3919aec62c21"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-29T07:09:31+00:00",
      "cve": "CVE-2026-97583",
      "id": "CVE-2026-97583",
      "initial_release_date": "2026-09-25T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "200",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: afs: Clear stale peer app data after address list changes",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97583.json",
      "version": "3"
    }
  }
}



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