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GHSA-8G97-85G6-9WHW

Vulnerability from github – Published: 2026-08-04 09:31 – Updated: 2026-08-04 09:31

Details

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

rhashtable: clear stale iter->p on table restart

rhashtable_walk_start_check() has two restart paths when resuming a walk. When iter->walker.tbl is valid, it re-validates iter->p against the table and sets iter->p = NULL if the object is gone. When iter->walker.tbl is NULL (table was freed during resize), it resets slot and skip but forgets to clear iter->p.

rhashtable_walk_next() then dereferences the stale iter->p, reading freed memory. This is a use-after-free.

Any caller that does multi-fragment rhashtable walks across walk_stop/walk_start boundaries is affected. Concrete cases include netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC (tipc_nl_sk_walk in net/tipc/socket.c).

Crash stack (netlink_diag): BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0 Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080) Call Trace: rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016) __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122) netlink_diag_dump+0xc2/0x240 netlink_dump+0x5bc/0x1270 netlink_recvmsg+0x7a3/0x980 sock_recvmsg+0x1bc/0x200 __sys_recvfrom+0x1d4/0x2c0

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64563"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-04T07:16:31Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrhashtable: clear stale iter-\u003ep on table restart\n\nrhashtable_walk_start_check() has two restart paths when resuming a walk.\nWhen iter-\u003ewalker.tbl is valid, it re-validates iter-\u003ep against the table\nand sets iter-\u003ep = NULL if the object is gone.  When iter-\u003ewalker.tbl is\nNULL (table was freed during resize), it resets slot and skip but forgets\nto clear iter-\u003ep.\n\nrhashtable_walk_next() then dereferences the stale iter-\u003ep, reading\nfreed memory.  This is a use-after-free.\n\nAny caller that does multi-fragment rhashtable walks across\nwalk_stop/walk_start boundaries is affected.  Concrete cases include\nnetlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC\n(tipc_nl_sk_walk in net/tipc/socket.c).\n\nCrash stack (netlink_diag):\n  BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0\n  Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)\n  Call Trace:\n   rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)\n   __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)\n   netlink_diag_dump+0xc2/0x240\n   netlink_dump+0x5bc/0x1270\n   netlink_recvmsg+0x7a3/0x980\n   sock_recvmsg+0x1bc/0x200\n   __sys_recvfrom+0x1d4/0x2c0",
  "id": "GHSA-8g97-85g6-9whw",
  "modified": "2026-08-04T09:31:35Z",
  "published": "2026-08-04T09:31:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64563"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64563 (GCVE-0-2026-64563)

Vulnerability from cvelistv5 – Published: 2026-08-04 06:23 – Updated: 2026-08-04 06:23

Title

rhashtable: clear stale iter->p on table restart

Summary

In the Linux kernel, the following vulnerability has been resolved: rhashtable: clear stale iter->p on table restart rhashtable_walk_start_check() has two restart paths when resuming a walk. When iter->walker.tbl is valid, it re-validates iter->p against the table and sets iter->p = NULL if the object is gone. When iter->walker.tbl is NULL (table was freed during resize), it resets slot and skip but forgets to clear iter->p. rhashtable_walk_next() then dereferences the stale iter->p, reading freed memory. This is a use-after-free. Any caller that does multi-fragment rhashtable walks across walk_stop/walk_start boundaries is affected. Concrete cases include netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC (tipc_nl_sk_walk in net/tipc/socket.c). Crash stack (netlink_diag): BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0 Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080) Call Trace: rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016) __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122) netlink_diag_dump+0xc2/0x240 netlink_dump+0x5bc/0x1270 netlink_recvmsg+0x7a3/0x980 sock_recvmsg+0x1bc/0x200 __sys_recvfrom+0x1d4/0x2c0

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa…
https://git.kernel.org/stable/c/4169d9fb92f313ff8…
https://git.kernel.org/stable/c/8173f7e2ce67e6ca1…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 3ff7c1dbf722cf3fa538672452ba182318e0fcc3 (git) Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3 (git) Affected: 5d240a8936f6a1d3ece06701e8c4d830a2eca8a8 , < 8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 (git)
Linux	Linux	Affected: 4.18 Unaffected: 0 , < 4.18 (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "lib/rhashtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3ff7c1dbf722cf3fa538672452ba182318e0fcc3",
              "status": "affected",
              "version": "5d240a8936f6a1d3ece06701e8c4d830a2eca8a8",
              "versionType": "git"
            },
            {
              "lessThan": "4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3",
              "status": "affected",
              "version": "5d240a8936f6a1d3ece06701e8c4d830a2eca8a8",
              "versionType": "git"
            },
            {
              "lessThan": "8173f7e2ce67e6ca1d4763f3da14e5b01ce77456",
              "status": "affected",
              "version": "5d240a8936f6a1d3ece06701e8c4d830a2eca8a8",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "lib/rhashtable.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.18"
            },
            {
              "lessThan": "4.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2-rc5",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2-rc5",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrhashtable: clear stale iter-\u003ep on table restart\n\nrhashtable_walk_start_check() has two restart paths when resuming a walk.\nWhen iter-\u003ewalker.tbl is valid, it re-validates iter-\u003ep against the table\nand sets iter-\u003ep = NULL if the object is gone.  When iter-\u003ewalker.tbl is\nNULL (table was freed during resize), it resets slot and skip but forgets\nto clear iter-\u003ep.\n\nrhashtable_walk_next() then dereferences the stale iter-\u003ep, reading\nfreed memory.  This is a use-after-free.\n\nAny caller that does multi-fragment rhashtable walks across\nwalk_stop/walk_start boundaries is affected.  Concrete cases include\nnetlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC\n(tipc_nl_sk_walk in net/tipc/socket.c).\n\nCrash stack (netlink_diag):\n  BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0\n  Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080)\n  Call Trace:\n   rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016)\n   __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122)\n   netlink_diag_dump+0xc2/0x240\n   netlink_dump+0x5bc/0x1270\n   netlink_recvmsg+0x7a3/0x980\n   sock_recvmsg+0x1bc/0x200\n   __sys_recvfrom+0x1d4/0x2c0"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-04T06:23:22.601Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3ff7c1dbf722cf3fa538672452ba182318e0fcc3"
        },
        {
          "url": "https://git.kernel.org/stable/c/4169d9fb92f313ff8e7e83d733c1ecdcc93eebd3"
        },
        {
          "url": "https://git.kernel.org/stable/c/8173f7e2ce67e6ca1d4763f3da14e5b01ce77456"
        }
      ],
      "title": "rhashtable: clear stale iter-\u003ep on table restart",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64563",
    "datePublished": "2026-08-04T06:23:22.601Z",
    "dateReserved": "2026-07-19T15:36:31.797Z",
    "dateUpdated": "2026-08-04T06:23:22.601Z",
    "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.

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-8G97-85G6-9WHW

CVE-2026-64563 (GCVE-0-2026-64563)

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Sightings

Nomenclature