CVE-2026-68399 (GCVE-0-2026-68399)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:04 – Updated: 2026-08-17 05:04
VLAI
Title
bpf: Fix UAF in sock clone early bailouts
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix UAF in sock clone early bailouts Similar to recent commit 9b51a6155d14 ("bpf,fork: wipe ->bpf_storage before bailouts that access it"), sk_clone() performs an initial shallow copy of the socket field ->sk_bpf_storage via sock_copy() for the cloned socket newsk. If sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior to calling bpf_sk_storage_clone(), newsk->sk_bpf_storage still points to the parent socket's BPF local storage. When newsk is subsequently freed via sk_free(), the deallocation path (__sk_destruct() -> bpf_sk_storage_free()) destroys the parent socket's BPF local storage, leading to a use-after-free (UAF) on the parent socket. Fix this by resetting newsk->sk_bpf_storage to NULL immediately after sock_copy() in sk_clone(), and remove the now redundant initialization from bpf_sk_storage_clone().
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 6ac99e8f23d4b10258406ca0dd7bffca5f31da9d , < 14b49b5ab29979552c219a09e569b424fbbf4a6e (git)
Affected: 6ac99e8f23d4b10258406ca0dd7bffca5f31da9d , < 7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f (git)
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Linux Linux Affected: 5.2
Unaffected: 0 , < 5.2 (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "programFiles": [
            "net/core/bpf_sk_storage.c",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix UAF in sock clone early bailouts\n\nSimilar to recent commit 9b51a6155d14 (\"bpf,fork: wipe -\u003ebpf_storage\nbefore bailouts that access it\"), sk_clone() performs an initial\nshallow copy of the socket field -\u003esk_bpf_storage via sock_copy()\nfor the cloned socket newsk.\n\nIf sk_clone() bails out early (e.g. if sk_filter_charge() fails) prior\nto calling bpf_sk_storage_clone(), newsk-\u003esk_bpf_storage still points\nto the parent socket\u0027s BPF local storage. When newsk is subsequently\nfreed via sk_free(), the deallocation path (__sk_destruct() -\u003e\nbpf_sk_storage_free()) destroys the parent socket\u0027s BPF local storage,\nleading to a use-after-free (UAF) on the parent socket.\n\nFix this by resetting newsk-\u003esk_bpf_storage to NULL immediately after\nsock_copy() in sk_clone(), and remove the now redundant initialization\nfrom bpf_sk_storage_clone()."
        }
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              "value": "AV:L - The vulnerable clone path and its early-bailout condition are driven through the BPF sk_storage subsystem and local socket setup (attaching sk_storage, attaching a socket filter, adjusting optmem_max). Per kernel guidance BPF is Local; a remote peer cannot control the bailout conditions.\nAC:L - An attacker who controls the local setup can deterministically force the early bailout by attaching a filter and lowering net.core.optmem_max below the filter size, exactly the sysctl-change scenario the code documents, making sk_filter_charge fail on every clone.\nPR:L - Reaching the bug requires attaching BPF sk_storage and manipulating socket/net settings; these capabilities (CAP_BPF/CAP_NET_ADMIN) can be reachable via user namespaces in some configurations, so the lower-privilege value is chosen per the higher-severity rule.\nUI:N - The clone is triggered by connection acceptance or association creation with no victim action; no user interaction is needed.\nS:U - The UAF corrupts kernel socket/BPF-storage objects within the kernel\u0027s own security authority; no crossing into a separate security scope (no VM/IOMMU boundary).\nC:H - The use-after-free lets the attacker reclaim the freed bpf_local_storage object with controlled contents, enabling disclosure of kernel memory; per guidance UAF is High.\nI:H - UAF on a live socket\u0027s BPF storage enables heap grooming and arbitrary-write primitives, giving control-flow hijack potential; per guidance UAF is High.\nA:H - Destroying the parent socket\u0027s still-referenced BPF local storage reliably causes memory corruption, oops, and kernel panic; per guidance any UAF/crash is High."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:04:47.842Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          "url": "https://git.kernel.org/stable/c/7cbd0c4cebe4c9f678d15e6b9ba975e1155a107f"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68399",
    "datePublished": "2026-08-10T12:04:18.837Z",
    "dateReserved": "2026-07-30T09:28:09.389Z",
    "dateUpdated": "2026-08-17T05:04:47.842Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
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      "current_release_date": "2026-08-13T23:29:32+00:00",
      "cve": "CVE-2026-68399",
      "id": "CVE-2026-68399",
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      "product_status:known_affected": "233",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Fix UAF in sock clone early bailouts",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68399.json",
      "version": "3"
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      "current_release_date": "2026-08-13T16:22:22Z",
      "cve": "CVE-2026-68399",
      "id": "CVE-2026-68399",
      "initial_release_date": "2026-08-13T16:22:22Z",
      "product_status:known_affected": "243",
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      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68399",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68399.json",
      "version": "2"
    }
  }
}



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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.
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  • 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.


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