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CVE-2025-68341 (GCVE-0-2025-68341)

Vulnerability from cvelistv5 – Published: 2025-12-23 13:58 – Updated: 2026-08-05 12:10
VLAI
Title
veth: reduce XDP no_direct return section to fix race
Summary
In the Linux kernel, the following vulnerability has been resolved: veth: reduce XDP no_direct return section to fix race As explain in commit fa349e396e48 ("veth: Fix race with AF_XDP exposing old or uninitialized descriptors") for veth there is a chance after napi_complete_done() that another CPU can manage start another NAPI instance running veth_pool(). For NAPI this is correctly handled as the napi_schedule_prep() check will prevent multiple instances from getting scheduled, but for the remaining code in veth_pool() this can run concurrent with the newly started NAPI instance. The problem/race is that xdp_clear_return_frame_no_direct() isn't designed to be nested. Prior to commit 401cb7dae813 ("net: Reference bpf_redirect_info via task_struct on PREEMPT_RT.") the temporary BPF net context bpf_redirect_info was stored per CPU, where this wasn't an issue. Since this commit the BPF context is stored in 'current' task_struct. When running veth in threaded-NAPI mode, then the kthread becomes the storage area. Now a race exists between two concurrent veth_pool() function calls one exiting NAPI and one running new NAPI, both using the same BPF net context. Race is when another CPU gets within the xdp_set_return_frame_no_direct() section before exiting veth_pool() calls the clear-function xdp_clear_return_frame_no_direct().
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < c1ceabcb347d1b0f7e70a7384ec7eff3847b7628 (git)
Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < d0bd018ad72a8a598ae709588934135017f8af52 (git)
Affected: 401cb7dae8130fd34eb84648e02ab4c506df7d5e , < a14602fcae17a3f1cb8a8521bedf31728f9e7e39 (git)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.61 , ≤ 6.12.* (semver)
Unaffected: 6.17.11 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/veth.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: reduce XDP no_direct return section to fix race\n\nAs explain in commit fa349e396e48 (\"veth: Fix race with AF_XDP exposing\nold or uninitialized descriptors\") for veth there is a chance after\nnapi_complete_done() that another CPU can manage start another NAPI\ninstance running veth_pool(). For NAPI this is correctly handled as the\nnapi_schedule_prep() check will prevent multiple instances from getting\nscheduled, but for the remaining code in veth_pool() this can run\nconcurrent with the newly started NAPI instance.\n\nThe problem/race is that xdp_clear_return_frame_no_direct() isn\u0027t\ndesigned to be nested.\n\nPrior to commit 401cb7dae813 (\"net: Reference bpf_redirect_info via\ntask_struct on PREEMPT_RT.\") the temporary BPF net context\nbpf_redirect_info was stored per CPU, where this wasn\u0027t an issue. Since\nthis commit the BPF context is stored in \u0027current\u0027 task_struct. When\nrunning veth in threaded-NAPI mode, then the kthread becomes the storage\narea. Now a race exists between two concurrent veth_pool() function calls\none exiting NAPI and one running new NAPI, both using the same BPF net\ncontext.\n\nRace is when another CPU gets within the xdp_set_return_frame_no_direct()\nsection before exiting veth_pool() calls the clear-function\nxdp_clear_return_frame_no_direct()."
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            }
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    "datePublished": "2025-12-23T13:58:26.749Z",
    "dateReserved": "2025-12-16T14:48:05.298Z",
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: reduce XDP no_direct return section to fix race\n\nAs explain in commit fa349e396e48 (\"veth: Fix race with AF_XDP exposing\nold or uninitialized descriptors\") for veth there is a chance after\nnapi_complete_done() that another CPU can manage start another NAPI\ninstance running veth_pool(). For NAPI this is correctly handled as the\nnapi_schedule_prep() check will prevent multiple instances from getting\nscheduled, but for the remaining code in veth_pool() this can run\nconcurrent with the newly started NAPI instance.\n\nThe problem/race is that xdp_clear_return_frame_no_direct() isn\u0027t\ndesigned to be nested.\n\nPrior to commit 401cb7dae813 (\"net: Reference bpf_redirect_info via\ntask_struct on PREEMPT_RT.\") the temporary BPF net context\nbpf_redirect_info was stored per CPU, where this wasn\u0027t an issue. Since\nthis commit the BPF context is stored in \u0027current\u0027 task_struct. When\nrunning veth in threaded-NAPI mode, then the kthread becomes the storage\narea. Now a race exists between two concurrent veth_pool() function calls\none exiting NAPI and one running new NAPI, both using the same BPF net\ncontext.\n\nRace is when another CPU gets within the xdp_set_return_frame_no_direct()\nsection before exiting veth_pool() calls the clear-function\nxdp_clear_return_frame_no_direct()."
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        "lastModified": "2026-07-30T06:24:39.323",
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      "current_release_date": "2026-07-30T10:07:32+00:00",
      "cve": "CVE-2025-68341",
      "id": "CVE-2025-68341",
      "initial_release_date": "2025-12-23T00:00:00+00:00",
      "product_status:known_affected": "90",
      "product_status:known_not_affected": "184",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: veth: reduce XDP no_direct return section to fix race",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-68341.json",
      "version": "3"
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    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-30T01:42:44Z",
      "cve": "CVE-2025-68341",
      "id": "CVE-2025-68341",
      "initial_release_date": "2025-12-24T00:24:05Z",
      "product_status:first_fixed": "2",
      "product_status:known_not_affected": "538",
      "product_status:recommended": "172",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-68341",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-68341.json",
      "version": "18"
    }
  }
}



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  • 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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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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