CVE-2023-53186 (GCVE-0-2023-53186)
Vulnerability from cvelistv5
Published
2025-09-15 14:04
Modified
2026-08-05 09:13
Severity ?
8.1 (High) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: skbuff: Fix a race between coalescing and releasing SKBs Commit 1effe8ca4e34 ("skbuff: fix coalescing for page_pool fragment recycling") allowed coalescing to proceed with non page pool page and page pool page when @from is cloned, i.e. to->pp_recycle --> false from->pp_recycle --> true skb_cloned(from) --> true However, it actually requires skb_cloned(@from) to hold true until coalescing finishes in this situation. If the other cloned SKB is released while the merging is in process, from_shinfo->nr_frags will be set to 0 toward the end of the function, causing the increment of frag page _refcount to be unexpectedly skipped resulting in inconsistent reference counts. Later when SKB(@to) is released, it frees the page directly even though the page pool page is still in use, leading to use-after-free or double-free errors. So it should be prohibited. The double-free error message below prompted us to investigate: BUG: Bad page state in process swapper/1 pfn:0e0d1 page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0xe0d1 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000 raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000 page dumped because: nonzero _refcount CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+ Call Trace: <IRQ> dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_pcp_prepare+0x260/0x2f0 free_unref_page+0x20/0x1c0 skb_release_data+0x10b/0x1a0 napi_consume_skb+0x56/0x150 net_rx_action+0xf0/0x350 ? __napi_schedule+0x79/0x90 __do_softirq+0xc8/0x2b1 __irq_exit_rcu+0xb9/0xf0 common_interrupt+0x82/0xa0 </IRQ> <TASK> asm_common_interrupt+0x22/0x40 RIP: 0010:default_idle+0xb/0x20
References
Impacted products
Vendor Product Version
Linux Linux Version: 53e0961da1c7bbdabd1abebb20de403ec237ec09
Version: 53e0961da1c7bbdabd1abebb20de403ec237ec09
Version: 53e0961da1c7bbdabd1abebb20de403ec237ec09
Version: 53e0961da1c7bbdabd1abebb20de403ec237ec09
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "906a6689bb0191ad2a44131a3377006aa098af59",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "71850b5af92da21b4862a9bc55bda61091247d00",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "5f692c992a3bb9a8018e3488098b401a4229e7ec",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            },
            {
              "lessThan": "0646dc31ca886693274df5749cd0c8c1eaaeb5ca",
              "status": "affected",
              "version": "53e0961da1c7bbdabd1abebb20de403ec237ec09",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.108",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.25",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.2.*",
              "status": "unaffected",
              "version": "6.2.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.108",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.25",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.2.12",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.3",
                  "versionStartIncluding": "5.15",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nskbuff: Fix a race between coalescing and releasing SKBs\n\nCommit 1effe8ca4e34 (\"skbuff: fix coalescing for page_pool fragment\nrecycling\") allowed coalescing to proceed with non page pool page and page\npool page when @from is cloned, i.e.\n\nto-\u003epp_recycle    --\u003e false\nfrom-\u003epp_recycle  --\u003e true\nskb_cloned(from)  --\u003e true\n\nHowever, it actually requires skb_cloned(@from) to hold true until\ncoalescing finishes in this situation. If the other cloned SKB is\nreleased while the merging is in process, from_shinfo-\u003enr_frags will be\nset to 0 toward the end of the function, causing the increment of frag\npage _refcount to be unexpectedly skipped resulting in inconsistent\nreference counts. Later when SKB(@to) is released, it frees the page\ndirectly even though the page pool page is still in use, leading to\nuse-after-free or double-free errors. So it should be prohibited.\n\nThe double-free error message below prompted us to investigate:\nBUG: Bad page state in process swapper/1  pfn:0e0d1\npage:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000\nindex:0x2 pfn:0xe0d1\nflags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)\nraw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000\nraw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000\npage dumped because: nonzero _refcount\n\nCPU: 1 PID: 0 Comm: swapper/1 Tainted: G            E      6.2.0+\nCall Trace:\n \u003cIRQ\u003e\ndump_stack_lvl+0x32/0x50\nbad_page+0x69/0xf0\nfree_pcp_prepare+0x260/0x2f0\nfree_unref_page+0x20/0x1c0\nskb_release_data+0x10b/0x1a0\nnapi_consume_skb+0x56/0x150\nnet_rx_action+0xf0/0x350\n? __napi_schedule+0x79/0x90\n__do_softirq+0xc8/0x2b1\n__irq_exit_rcu+0xb9/0xf0\ncommon_interrupt+0x82/0xa0\n\u003c/IRQ\u003e\n\u003cTASK\u003e\nasm_common_interrupt+0x22/0x40\nRIP: 0010:default_idle+0xb/0x20"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - skb_try_coalesce() is reached from the TCP receive path (tcp_try_coalesce/tcp_queue_rcv) and IP defrag while processing inbound packets on page_pool NICs; a remote peer sending TCP segments to a listening service drives the vulnerable coalesce without local code execution.\nAC:H - The bug is a TOCTOU on skb_cloned(from) between the pp_recycle admission check and the later nr_frags/__skb_frag_ref logic; winning it requires a sibling clone (typically from AF_PACKET/monitoring or bridge fanout) to be released on another CPU during that window, which a pure remote sender cannot fully control.\nPR:N - Exploitation uses unauthenticated network traffic to an already-exposed TCP/IP service; packet taps or bridging that create clones are victim-side deployment state, not credentials or capabilities the attacker must hold on the host.\nUI:N - Coalescing runs in softirq/NAPI receive context on packet arrival; no user action such as mounting, opening a file, or confirming a prompt is required.\nS:U - The resulting page use-after-free/double-free corrupts host kernel memory within the same OS authority; it is not a VM escape, IOMMU bypass, or sandbox boundary cross.\nC:H - The race skips __skb_frag_ref while still attaching frags to @to, then frees page_pool pages still in use\u2014classic page UAF that can be groomed for arbitrary kernel memory disclosure.\nI:H - The same UAF/double-free of page_pool pages yields heap aliasing and write primitives suitable for control-flow hijacking, matching kernel guidance that exploitable UAF is Integrity High.\nA:H - The fix commit documents a reproducible BUG/bad-page-state crash in skb_release_data\u2192free_unref_page from net_rx softirq, so availability impact is a full kernel oops/panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T09:13:00.022Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/906a6689bb0191ad2a44131a3377006aa098af59"
        },
        {
          "url": "https://git.kernel.org/stable/c/71850b5af92da21b4862a9bc55bda61091247d00"
        },
        {
          "url": "https://git.kernel.org/stable/c/5f692c992a3bb9a8018e3488098b401a4229e7ec"
        },
        {
          "url": "https://git.kernel.org/stable/c/0646dc31ca886693274df5749cd0c8c1eaaeb5ca"
        }
      ],
      "title": "skbuff: Fix a race between coalescing and releasing SKBs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2023-53186",
    "datePublished": "2025-09-15T14:04:38.954Z",
    "dateReserved": "2025-09-15T13:59:19.066Z",
    "dateUpdated": "2026-08-05T09:13:00.022Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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