Vulnerability-Lookup

GHSA-FP4W-89FW-H8P4

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31

Details

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

mm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host

lookup_swap_cgroup_id() passes swap_cgroup_ctrl[type].map to __swap_cgroup_id_lookup() without checking that the type was ever registered via swap_cgroup_swapon(). On a swapless host every ctrl->map is NULL, so __swap_cgroup_id_lookup() dereferences NULL + a scaled swp_offset().

Since commit bea67dcc5eea ("mm: attempt to batch free swap entries for zap_pte_range()"), zap_pte_range() -> swap_pte_batch() calls lookup_swap_cgroup_id() on any non-present, non-none PTE that decodes as a real swap entry, without first validating it against swap_info[]. A single PTE corrupted into a type-0 swap entry takes the host down at process exit.

We hit this in production on a swapless 6.12.58 host: ~1s of "get_swap_device: Bad swap file entry 3f800204222bb" (do_swap_page() being correctly defensive about the same entry) followed by

BUG: unable to handle page fault for address: 000003f800204220 RIP: 0010:lookup_swap_cgroup_id+0x2b/0x60 Call Trace: swap_pte_batch+0xbf/0x230 zap_pte_range+0x4c8/0x780 unmap_page_range+0x190/0x3e0 exit_mmap+0xd9/0x3c0 do_exit+0x20c/0x4b0

syzbot has reported the identical stack.

The source of the PTE corruption is a separate bug; this change makes the teardown path as robust as the fault path already is. Every other caller of lookup_swap_cgroup_id() is downstream of a get_swap_device() that has already validated the entry, so the new branch is cold.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-64416"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:25Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host\n\nlookup_swap_cgroup_id() passes swap_cgroup_ctrl[type].map to\n__swap_cgroup_id_lookup() without checking that the type was ever\nregistered via swap_cgroup_swapon().  On a swapless host every ctrl-\u003emap\nis NULL, so __swap_cgroup_id_lookup() dereferences NULL + a scaled\nswp_offset().\n\nSince commit bea67dcc5eea (\"mm: attempt to batch free swap entries for\nzap_pte_range()\"), zap_pte_range() -\u003e swap_pte_batch() calls\nlookup_swap_cgroup_id() on any non-present, non-none PTE that decodes as a\nreal swap entry, without first validating it against swap_info[].  A\nsingle PTE corrupted into a type-0 swap entry takes the host down at\nprocess exit.\n\nWe hit this in production on a swapless 6.12.58 host: ~1s of\n\"get_swap_device: Bad swap file entry 3f800204222bb\" (do_swap_page() being\ncorrectly defensive about the same entry) followed by\n\n  BUG: unable to handle page fault for address: 000003f800204220\n  RIP: 0010:lookup_swap_cgroup_id+0x2b/0x60\n  Call Trace:\n   swap_pte_batch+0xbf/0x230\n   zap_pte_range+0x4c8/0x780\n   unmap_page_range+0x190/0x3e0\n   exit_mmap+0xd9/0x3c0\n   do_exit+0x20c/0x4b0\n\nsyzbot has reported the identical stack.\n\nThe source of the PTE corruption is a separate bug; this change makes the\nteardown path as robust as the fault path already is.  Every other caller\nof lookup_swap_cgroup_id() is downstream of a get_swap_device() that has\nalready validated the entry, so the new branch is cold.",
  "id": "GHSA-fp4w-89fw-h8p4",
  "modified": "2026-07-25T12:31:34Z",
  "published": "2026-07-25T12:31:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64416"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/63b02a9409cb5180398491b093e48bcb5315f5fb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6a4196d19f477524d2f92adca90fc1fbe9a0420a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/818416fef38759f23210de449663cd9d7e293d39"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b415c00bf23df577a4a95673d00ae76687bcc1d4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-64416 (GCVE-0-2026-64416)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:50 – Updated: 2026-07-25 08:50

Title

mm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host

Summary

In the Linux kernel, the following vulnerability has been resolved: mm: swap_cgroup: fix NULL deref in lookup_swap_cgroup_id on swapless host lookup_swap_cgroup_id() passes swap_cgroup_ctrl[type].map to __swap_cgroup_id_lookup() without checking that the type was ever registered via swap_cgroup_swapon(). On a swapless host every ctrl->map is NULL, so __swap_cgroup_id_lookup() dereferences NULL + a scaled swp_offset(). Since commit bea67dcc5eea ("mm: attempt to batch free swap entries for zap_pte_range()"), zap_pte_range() -> swap_pte_batch() calls lookup_swap_cgroup_id() on any non-present, non-none PTE that decodes as a real swap entry, without first validating it against swap_info[]. A single PTE corrupted into a type-0 swap entry takes the host down at process exit. We hit this in production on a swapless 6.12.58 host: ~1s of "get_swap_device: Bad swap file entry 3f800204222bb" (do_swap_page() being correctly defensive about the same entry) followed by BUG: unable to handle page fault for address: 000003f800204220 RIP: 0010:lookup_swap_cgroup_id+0x2b/0x60 Call Trace: swap_pte_batch+0xbf/0x230 zap_pte_range+0x4c8/0x780 unmap_page_range+0x190/0x3e0 exit_mmap+0xd9/0x3c0 do_exit+0x20c/0x4b0 syzbot has reported the identical stack. The source of the PTE corruption is a separate bug; this change makes the teardown path as robust as the fault path already is. Every other caller of lookup_swap_cgroup_id() is downstream of a get_swap_device() that has already validated the entry, so the new branch is cold.

Severity

No CVSS data available.

Assigner

Linux

References

4 references

URL	Tags
https://git.kernel.org/stable/c/818416fef38759f23…
https://git.kernel.org/stable/c/b415c00bf23df577a…
https://git.kernel.org/stable/c/6a4196d19f477524d…
https://git.kernel.org/stable/c/63b02a9409cb51803…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bea67dcc5eea0f6a213897a59b9e644977cd07e6 , < 818416fef38759f23210de449663cd9d7e293d39 (git) Affected: bea67dcc5eea0f6a213897a59b9e644977cd07e6 , < b415c00bf23df577a4a95673d00ae76687bcc1d4 (git) Affected: bea67dcc5eea0f6a213897a59b9e644977cd07e6 , < 6a4196d19f477524d2f92adca90fc1fbe9a0420a (git) Affected: bea67dcc5eea0f6a213897a59b9e644977cd07e6 , < 63b02a9409cb5180398491b093e48bcb5315f5fb (git)
Linux	Linux	Affected: 6.12 Unaffected: 0 , < 6.12 (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2-rc1 , ≤ * (original_commit_for_fix)

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JSON

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        {
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          "programFiles": [
            "mm/swap_cgroup.c"
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              "version": "6.12"
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          "url": "https://git.kernel.org/stable/c/63b02a9409cb5180398491b093e48bcb5315f5fb"
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    "datePublished": "2026-07-25T08:50:55.997Z",
    "dateReserved": "2026-07-19T15:36:31.786Z",
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}

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-FP4W-89FW-H8P4

CVE-2026-64416 (GCVE-0-2026-64416)

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Sightings

Nomenclature