CVE-2025-38453 (GCVE-0-2025-38453)
Vulnerability from cvelistv5
Published
2025-07-25 15:27
Modified
2026-08-05 12:02
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/msg_ring: ensure io_kiocb freeing is deferred for RCU syzbot reports that defer/local task_work adding via msg_ring can hit a request that has been freed: CPU: 1 UID: 0 PID: 19356 Comm: iou-wrk-19354 Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xd2/0x2b0 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 io_req_local_work_add io_uring/io_uring.c:1184 [inline] __io_req_task_work_add+0x589/0x950 io_uring/io_uring.c:1252 io_msg_remote_post io_uring/msg_ring.c:103 [inline] io_msg_data_remote io_uring/msg_ring.c:133 [inline] __io_msg_ring_data+0x820/0xaa0 io_uring/msg_ring.c:151 io_msg_ring_data io_uring/msg_ring.c:173 [inline] io_msg_ring+0x134/0xa00 io_uring/msg_ring.c:314 __io_issue_sqe+0x17e/0x4b0 io_uring/io_uring.c:1739 io_issue_sqe+0x165/0xfd0 io_uring/io_uring.c:1762 io_wq_submit_work+0x6e9/0xb90 io_uring/io_uring.c:1874 io_worker_handle_work+0x7cd/0x1180 io_uring/io-wq.c:642 io_wq_worker+0x42f/0xeb0 io_uring/io-wq.c:696 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK> which is supposed to be safe with how requests are allocated. But msg ring requests alloc and free on their own, and hence must defer freeing to a sane time. Add an rcu_head and use kfree_rcu() in both spots where requests are freed. Only the one in io_msg_tw_complete() is strictly required as it has been visible on the other ring, but use it consistently in the other spot as well. This should not cause any other issues outside of KASAN rightfully complaining about it.
References
Impacted products
Vendor Product Version
Linux Linux Version: 0617bb500bfabf8447062f1e1edde92ed2b638f1
Version: 0617bb500bfabf8447062f1e1edde92ed2b638f1
Version: 0617bb500bfabf8447062f1e1edde92ed2b638f1
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/io_uring_types.h",
            "io_uring/msg_ring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "094ba14a471cc6c68078c7ad488539eaf32c2277",
              "status": "affected",
              "version": "0617bb500bfabf8447062f1e1edde92ed2b638f1",
              "versionType": "git"
            },
            {
              "lessThan": "e5b3432f4a6b418b8bd8fc91f38efbf17a77167a",
              "status": "affected",
              "version": "0617bb500bfabf8447062f1e1edde92ed2b638f1",
              "versionType": "git"
            },
            {
              "lessThan": "fc582cd26e888b0652bc1494f252329453fd3b23",
              "status": "affected",
              "version": "0617bb500bfabf8447062f1e1edde92ed2b638f1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/io_uring_types.h",
            "io_uring/msg_ring.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.46",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15.7",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/msg_ring: ensure io_kiocb freeing is deferred for RCU\n\nsyzbot reports that defer/local task_work adding via msg_ring can hit\na request that has been freed:\n\nCPU: 1 UID: 0 PID: 19356 Comm: iou-wrk-19354 Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full)\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:408 [inline]\n print_report+0xd2/0x2b0 mm/kasan/report.c:521\n kasan_report+0x118/0x150 mm/kasan/report.c:634\n io_req_local_work_add io_uring/io_uring.c:1184 [inline]\n __io_req_task_work_add+0x589/0x950 io_uring/io_uring.c:1252\n io_msg_remote_post io_uring/msg_ring.c:103 [inline]\n io_msg_data_remote io_uring/msg_ring.c:133 [inline]\n __io_msg_ring_data+0x820/0xaa0 io_uring/msg_ring.c:151\n io_msg_ring_data io_uring/msg_ring.c:173 [inline]\n io_msg_ring+0x134/0xa00 io_uring/msg_ring.c:314\n __io_issue_sqe+0x17e/0x4b0 io_uring/io_uring.c:1739\n io_issue_sqe+0x165/0xfd0 io_uring/io_uring.c:1762\n io_wq_submit_work+0x6e9/0xb90 io_uring/io_uring.c:1874\n io_worker_handle_work+0x7cd/0x1180 io_uring/io-wq.c:642\n io_wq_worker+0x42f/0xeb0 io_uring/io-wq.c:696\n ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148\n ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245\n \u003c/TASK\u003e\n\nwhich is supposed to be safe with how requests are allocated. But msg\nring requests alloc and free on their own, and hence must defer freeing\nto a sane time.\n\nAdd an rcu_head and use kfree_rcu() in both spots where requests are\nfreed. Only the one in io_msg_tw_complete() is strictly required as it\nhas been visible on the other ring, but use it consistently in the other\nspot as well.\n\nThis should not cause any other issues outside of KASAN rightfully\ncomplaining about it."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerability is reached purely through the io_uring syscall interface (`io_uring_setup()` plus `io_uring_enter()` submitting `IORING_OP_MSG_RING`), requiring local access to the machine or a container on it. Per kernel scoring guidance io_uring bugs are Local.\nAC:L - The attacker creates and fully controls both sides of the race \u2014 the target ring (with `IORING_SETUP_DEFER_TASKRUN|SINGLE_ISSUER`), the flood of MSG_RING requests from io-wq workers on one CPU, and the reaping task that frees those requests on another \u2014 so it can be hit repeatedly at will, as syzbot\u0027s reproducer demonstrates. No precondition lies outside the attacker\u0027s influence; the required ring flags are runtime choices, not a rare build config.\nPR:L - Any unprivileged local user can create io_uring instances and submit `IORING_OP_MSG_RING`; there is no capability, credential, or LSM gate anywhere along `io_msg_ring() \u2192 io_msg_data_remote() \u2192 io_req_local_work_add()`, and `kernel.io_uring_disabled` is 0 by default. The path is equally reachable from inside an unprivileged container or user namespace.\nUI:N - Exploitation is entirely self-driven by the attacker\u0027s own two threads submitting and reaping io_uring requests. No victim action, mount, or file access is involved.\nS:U - The freed `io_kiocb` and the code dereferencing it both live in the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed. Standard kernel-local impact.\nC:H - A freed `io_kiocb` from the shared `req_cachep` slab is dereferenced after `kmem_cache_free()`, and an attacker who grooms slab reuse controls what object occupies that memory when it is read. Consistent with treating use-after-free as enabling attacker-influenced disclosure of kernel memory contents, this is High.\nI:H - The stale read feeds the `nr_tw` value written into the newly queued request and drives the task-wakeup decision, so freed/reallocated memory directly influences kernel control state. Use-after-free conditions on a heap-spray-friendly cache such as `io_kiocb` are treated as High integrity impact.\nA:H - This is a confirmed KASAN slab-use-after-free that panics kernels built with KASAN or `panic_on_warn`, and on production kernels a garbage `nr_tw_prev` can exceed `cq_wait_nr` and suppress the `wake_up_state()` of the target ring\u0027s submitter, stalling a task that is waiting on already-queued work. Both outcomes are triggerable repeatedly by an unprivileged user."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:02:00.377Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/094ba14a471cc6c68078c7ad488539eaf32c2277"
        },
        {
          "url": "https://git.kernel.org/stable/c/e5b3432f4a6b418b8bd8fc91f38efbf17a77167a"
        },
        {
          "url": "https://git.kernel.org/stable/c/fc582cd26e888b0652bc1494f252329453fd3b23"
        }
      ],
      "title": "io_uring/msg_ring: ensure io_kiocb freeing is deferred for RCU",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38453",
    "datePublished": "2025-07-25T15:27:33.374Z",
    "dateReserved": "2025-04-16T04:51:24.018Z",
    "dateUpdated": "2026-08-05T12:02:00.377Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.