CVE-2025-38270 (GCVE-0-2025-38270)
Vulnerability from cvelistv5
Published
2025-07-10 07:41
Modified
2026-08-05 12:00
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: net: drv: netdevsim: don't napi_complete() from netpoll netdevsim supports netpoll. Make sure we don't call napi_complete() from it, since it may not be scheduled. Breno reports hitting a warning in napi_complete_done(): WARNING: CPU: 14 PID: 104 at net/core/dev.c:6592 napi_complete_done+0x2cc/0x560 __napi_poll+0x2d8/0x3a0 handle_softirqs+0x1fe/0x710 This is presumably after netpoll stole the SCHED bit prematurely.
References
Impacted products
Vendor Product Version
Linux Linux Version: 3762ec05a9fbda16aaaa2568df679ab8ad13f38d
Version: 3762ec05a9fbda16aaaa2568df679ab8ad13f38d
Version: 3762ec05a9fbda16aaaa2568df679ab8ad13f38d
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/netdevsim/netdev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "a8ff2e362d901200a1075c3ca9c56d9c7bbef389",
              "status": "affected",
              "version": "3762ec05a9fbda16aaaa2568df679ab8ad13f38d",
              "versionType": "git"
            },
            {
              "lessThan": "6837dd877270c57689bd866de9f3de14172c2439",
              "status": "affected",
              "version": "3762ec05a9fbda16aaaa2568df679ab8ad13f38d",
              "versionType": "git"
            },
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              "status": "affected",
              "version": "3762ec05a9fbda16aaaa2568df679ab8ad13f38d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/netdevsim/netdev.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.10"
            },
            {
              "lessThan": "6.10",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.3",
              "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": "6.12.34",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15.3",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16",
                  "versionStartIncluding": "6.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: drv: netdevsim: don\u0027t napi_complete() from netpoll\n\nnetdevsim supports netpoll. Make sure we don\u0027t call napi_complete()\nfrom it, since it may not be scheduled. Breno reports hitting a\nwarning in napi_complete_done():\n\nWARNING: CPU: 14 PID: 104 at net/core/dev.c:6592 napi_complete_done+0x2cc/0x560\n  __napi_poll+0x2d8/0x3a0\n  handle_softirqs+0x1fe/0x710\n\nThis is presumably after netpoll stole the SCHED bit prematurely."
        }
      ],
      "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 - netdevsim is a purely software-simulated netdev with no physical link; the vulnerable `nsim_poll()` is reached by transmitting on a local netdevsim interface (`nsim_start_xmit` \u2192 `nsim_napi_rx` \u2192 `napi_schedule`) or via a locally configured netconsole/netpoll. There is no path from unsolicited remote traffic in a default configuration.\nAC:L - The attacker fully controls both the trigger and the race: queuing \u226564 skbs on one RX ring makes `nsim_rcv()` return the full budget deterministically, and concurrent `napi_schedule()` from a second thread on another CPU is trivially arranged by multi-threaded sending. No condition depends on state outside the attacker\u0027s influence.\nPR:L - Given a netdevsim interface present in the attacker\u0027s network namespace (a routine setup on CI/test hosts and in admin-provisioned containers), an ordinary unprivileged local user can drive the RX ring to full budget simply by sending packets \u2014 no capability check guards `nsim_start_xmit()` or the NAPI poll path.\nUI:N - The condition is triggered entirely by the attacker\u0027s own packet transmission and softirq NAPI processing; no victim action of any kind is needed.\nS:U - The corrupted state (NAPI `state` bits, `poll_list`, GRO lists) and the resulting impact are all within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Clearing `NAPIF_STATE_SCHED` while still owning the instance destroys NAPI\u0027s only mutual-exclusion guarantee (netpoll_poll_lock is a no-op without netpoll), allowing two CPUs to run the same NAPI concurrently over shared `napi-\u003egro` and skb lists; the resulting list corruption/UAF is leverageable to read adjacent kernel memory.\nI:H - A `list_add_tail()` of an already-linked `poll_list` node onto a second CPU\u0027s poll list is an unlinked-pointer write into kernel list structures, and concurrent GRO/skb-queue manipulation yields further heap corruption \u2014 both classic primitives for controlled kernel memory writes.\nA:H - The reported symptom is a `WARN_ON_ONCE` in `napi_complete_done()` (fatal under `panic_on_warn`), and the NAPI-state desync additionally causes list corruption, `pr_crit` under `CONFIG_DEBUG_NET`, softirq loops, and oopses that take down the machine."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:00:52.836Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/a8ff2e362d901200a1075c3ca9c56d9c7bbef389"
        },
        {
          "url": "https://git.kernel.org/stable/c/6837dd877270c57689bd866de9f3de14172c2439"
        },
        {
          "url": "https://git.kernel.org/stable/c/1264971017b4d7141352a7fe29021bdfce5d885d"
        }
      ],
      "title": "net: drv: netdevsim: don\u0027t napi_complete() from netpoll",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38270",
    "datePublished": "2025-07-10T07:41:52.475Z",
    "dateReserved": "2025-04-16T04:51:23.998Z",
    "dateUpdated": "2026-08-05T12:00:52.836Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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