Vulnerability-Lookup

GHSA-3GC2-W5W2-FFCH

Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31

Details

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

xfrm: iptfs: reset runtime state when cloning SAs

iptfs_clone_state() clones the IPTFS mode data with kmemdup(). This copies runtime objects which must not be shared with the original SA, including the embedded sk_buff_head, hrtimers, spinlock, and in-flight reassembly/reorder state.

If xfrm_state_migrate() fails after clone_state() but before the later init_state() call has reinitialized those fields, the cloned state can be destroyed by xfrm_state_gc_task() with list and timer state copied from the original SA. With queued packets this lets the clone splice and free skbs owned by the original IPTFS queue, leading to use-after-free and double-free reports in iptfs_destroy_state() and skb release paths.

Reinitialize the clone's runtime state before publishing it through x->mode_data. Because clone_state() now publishes a destroyable mode_data object before init_state(), take the mode callback module reference there. Avoid taking it again from __iptfs_init_state() for the same object.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-63911"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-19T16:17:08Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: reset runtime state when cloning SAs\n\niptfs_clone_state() clones the IPTFS mode data with kmemdup(). This\ncopies runtime objects which must not be shared with the original SA,\nincluding the embedded sk_buff_head, hrtimers, spinlock, and in-flight\nreassembly/reorder state.\n\nIf xfrm_state_migrate() fails after clone_state() but before the later\ninit_state() call has reinitialized those fields, the cloned state can be\ndestroyed by xfrm_state_gc_task() with list and timer state copied from the\noriginal SA. With queued packets this lets the clone splice and free skbs\nowned by the original IPTFS queue, leading to use-after-free and\ndouble-free reports in iptfs_destroy_state() and skb release paths.\n\nReinitialize the clone\u0027s runtime state before publishing it through\nx-\u003emode_data. Because clone_state() now publishes a destroyable mode_data\nobject before init_state(), take the mode callback module reference there.\nAvoid taking it again from __iptfs_init_state() for the same object.",
  "id": "GHSA-3gc2-w5w2-ffch",
  "modified": "2026-07-20T15:31:50Z",
  "published": "2026-07-19T18:31:45Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63911"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7f83d174073234839aea176f265e517e0d50a1d2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9327252e04626d4bb02ca8c0c108fbe8eabf0c5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfb9f6cbfa9826655a49698cf90eb800fce2178e"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-63911 (GCVE-0-2026-63911)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-08-05 12:37

Title

xfrm: iptfs: reset runtime state when cloning SAs

Summary

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: reset runtime state when cloning SAs iptfs_clone_state() clones the IPTFS mode data with kmemdup(). This copies runtime objects which must not be shared with the original SA, including the embedded sk_buff_head, hrtimers, spinlock, and in-flight reassembly/reorder state. If xfrm_state_migrate() fails after clone_state() but before the later init_state() call has reinitialized those fields, the cloned state can be destroyed by xfrm_state_gc_task() with list and timer state copied from the original SA. With queued packets this lets the clone splice and free skbs owned by the original IPTFS queue, leading to use-after-free and double-free reports in iptfs_destroy_state() and skb release paths. Reinitialize the clone's runtime state before publishing it through x->mode_data. Because clone_state() now publishes a destroyable mode_data object before init_state(), take the mode callback module reference there. Avoid taking it again from __iptfs_init_state() for the same object.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/9327252e04626d4bb…
https://git.kernel.org/stable/c/dfb9f6cbfa9826655…
https://git.kernel.org/stable/c/7f83d174073234839…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 0e4fbf013fa566f274ce9b4ce698c75b1f998c52 , < 9327252e04626d4bb02ca8c0c108fbe8eabf0c5a (git) Affected: 0e4fbf013fa566f274ce9b4ce698c75b1f998c52 , < dfb9f6cbfa9826655a49698cf90eb800fce2178e (git) Affected: 0e4fbf013fa566f274ce9b4ce698c75b1f998c52 , < 7f83d174073234839aea176f265e517e0d50a1d2 (git)
Linux	Linux	Affected: 6.14 Unaffected: 0 , < 6.14 (semver) Unaffected: 6.18.35 , ≤ 6.18.* (semver) Unaffected: 7.0.12 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
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    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/xfrm/xfrm_iptfs.c"
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              "lessThan": "7f83d174073234839aea176f265e517e0d50a1d2",
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          "versions": [
            {
              "status": "affected",
              "version": "6.14"
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              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
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              "status": "unaffected",
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              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.0.12",
              "versionType": "semver"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: iptfs: reset runtime state when cloning SAs\n\niptfs_clone_state() clones the IPTFS mode data with kmemdup(). This\ncopies runtime objects which must not be shared with the original SA,\nincluding the embedded sk_buff_head, hrtimers, spinlock, and in-flight\nreassembly/reorder state.\n\nIf xfrm_state_migrate() fails after clone_state() but before the later\ninit_state() call has reinitialized those fields, the cloned state can be\ndestroyed by xfrm_state_gc_task() with list and timer state copied from the\noriginal SA. With queued packets this lets the clone splice and free skbs\nowned by the original IPTFS queue, leading to use-after-free and\ndouble-free reports in iptfs_destroy_state() and skb release paths.\n\nReinitialize the clone\u0027s runtime state before publishing it through\nx-\u003emode_data. Because clone_state() now publishes a destroyable mode_data\nobject before init_state(), take the mode callback module reference there.\nAvoid taking it again from __iptfs_init_state() for the same object."
        }
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              "value": "AV:L - The bug is reached only through local XFRM SA migration via netlink XFRM_MSG_MIGRATE or PF_KEY SADB_X_MIGRATE, not by processing remote network packets alone.\nAC:L - On systems with IPTFS and XFRM_MIGRATE enabled, an attacker who controls the migrate request can reliably queue skbs on the SA and force a post-clone migration failure to trigger the shared-queue teardown.\nPR:L - All XFRM migrate operations require CAP_NET_ADMIN on the target network namespace, which unprivileged users can obtain inside a user namespace via unshare.\nUI:N - Exploitation requires no victim interaction beyond the attacker\u2019s own netlink/PF_KEY operations and traffic through an SA they control.\nS:U - Impact is kernel memory corruption and privilege escalation within the same kernel security authority, not a cross-VM or cross-IOMMU boundary escape.\nC:H - The bug is a use-after-free on sk_buff objects where the clone\u2019s destroy path frees skbs still owned by the live original IPTFS queue, enabling arbitrary kernel memory read primitives.\nI:H - Shared queue/timer state corruption and skb double-free provide exploitable heap corruption that can be leveraged for arbitrary kernel writes or code execution.\nA:H - The vulnerability causes kernel oops/panic from UAF and double-free in skb release paths, and can be used for repeatable denial of service against the host."
            }
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        "dateUpdated": "2026-08-05T12:37:05.089Z",
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        {
          "url": "https://git.kernel.org/stable/c/7f83d174073234839aea176f265e517e0d50a1d2"
        }
      ],
      "title": "xfrm: iptfs: reset runtime state when cloning SAs",
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        "engine": "bippy-1.2.0"
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    "cveId": "CVE-2026-63911",
    "datePublished": "2026-07-19T14:55:16.496Z",
    "dateReserved": "2026-07-19T07:54:57.020Z",
    "dateUpdated": "2026-08-05T12:37:05.089Z",
    "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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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