CVE-2026-22979 (GCVE-0-2026-22979)

Vulnerability from cvelistv5 – Published: 2026-01-23 15:24 – Updated: 2026-02-09 08:36
VLAI?
Title
net: fix memory leak in skb_segment_list for GRO packets
Summary
In the Linux kernel, the following vulnerability has been resolved: net: fix memory leak in skb_segment_list for GRO packets When skb_segment_list() is called during packet forwarding, it handles packets that were aggregated by the GRO engine. Historically, the segmentation logic in skb_segment_list assumes that individual segments are split from a parent SKB and may need to carry their own socket memory accounting. Accordingly, the code transfers truesize from the parent to the newly created segments. Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this truesize subtraction in skb_segment_list() was valid because fragments still carry a reference to the original socket. However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed this behavior by ensuring that fraglist entries are explicitly orphaned (skb->sk = NULL) to prevent illegal orphaning later in the stack. This change meant that the entire socket memory charge remained with the head SKB, but the corresponding accounting logic in skb_segment_list() was never updated. As a result, the current code unconditionally adds each fragment's truesize to delta_truesize and subtracts it from the parent SKB. Since the fragments are no longer charged to the socket, this subtraction results in an effective under-count of memory when the head is freed. This causes sk_wmem_alloc to remain non-zero, preventing socket destruction and leading to a persistent memory leak. The leak can be observed via KMEMLEAK when tearing down the networking environment: unreferenced object 0xffff8881e6eb9100 (size 2048): comm "ping", pid 6720, jiffies 4295492526 backtrace: kmem_cache_alloc_noprof+0x5c6/0x800 sk_prot_alloc+0x5b/0x220 sk_alloc+0x35/0xa00 inet6_create.part.0+0x303/0x10d0 __sock_create+0x248/0x640 __sys_socket+0x11b/0x1d0 Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST packets constructed by GRO, the truesize adjustment is removed. The call to skb_release_head_state() must be preserved. As documented in commit cf673ed0e057 ("net: fix fraglist segmentation reference count leak"), it is still required to correctly drop references to SKB extensions that may be overwritten during __copy_skb_header().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 2eeab8c47c3c0276e0746bc382f405c9a236a5ad , < 0b27828ebd1ed3107d7929c3737adbe862e99e74 (git)
Affected: fc126c1d51e9552eacd2d717b9ffe9262a8a4cd6 , < 88bea149db2057112af3aaf63534b24fab5858ab (git)
Affected: ed4cccef64c1d0d5b91e69f7a8a6697c3a865486 , < 3264881431e308b9c72cb8a0159d57a56d67dd79 (git)
Affected: ed4cccef64c1d0d5b91e69f7a8a6697c3a865486 , < c114a32a2e70b82d447f409f7ffcfa3058f9d5bd (git)
Affected: ed4cccef64c1d0d5b91e69f7a8a6697c3a865486 , < 238e03d0466239410b72294b79494e43d4fabe77 (git)
Affected: d225b0ac96dc40d7e8ae2bc227eb2c56e130975f (git)
Affected: 5b3b67f731296027cceb3efad881ae281213f86f (git)
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    Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.1.161 , ≤ 6.1.* (semver)
Unaffected: 6.6.121 , ≤ 6.6.* (semver)
Unaffected: 6.12.66 , ≤ 6.12.* (semver)
Unaffected: 6.18.6 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/skbuff.c"
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          "product": "Linux",
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          "vendor": "Linux",
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              "version": "6.18.6",
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              "version": "6.19",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix memory leak in skb_segment_list for GRO packets\n\nWhen skb_segment_list() is called during packet forwarding, it handles\npackets that were aggregated by the GRO engine.\n\nHistorically, the segmentation logic in skb_segment_list assumes that\nindividual segments are split from a parent SKB and may need to carry\ntheir own socket memory accounting. Accordingly, the code transfers\ntruesize from the parent to the newly created segments.\n\nPrior to commit ed4cccef64c1 (\"gro: fix ownership transfer\"), this\ntruesize subtraction in skb_segment_list() was valid because fragments\nstill carry a reference to the original socket.\n\nHowever, commit ed4cccef64c1 (\"gro: fix ownership transfer\") changed\nthis behavior by ensuring that fraglist entries are explicitly\norphaned (skb-\u003esk = NULL) to prevent illegal orphaning later in the\nstack. This change meant that the entire socket memory charge remained\nwith the head SKB, but the corresponding accounting logic in\nskb_segment_list() was never updated.\n\nAs a result, the current code unconditionally adds each fragment\u0027s\ntruesize to delta_truesize and subtracts it from the parent SKB. Since\nthe fragments are no longer charged to the socket, this subtraction\nresults in an effective under-count of memory when the head is freed.\nThis causes sk_wmem_alloc to remain non-zero, preventing socket\ndestruction and leading to a persistent memory leak.\n\nThe leak can be observed via KMEMLEAK when tearing down the networking\nenvironment:\n\nunreferenced object 0xffff8881e6eb9100 (size 2048):\n  comm \"ping\", pid 6720, jiffies 4295492526\n  backtrace:\n    kmem_cache_alloc_noprof+0x5c6/0x800\n    sk_prot_alloc+0x5b/0x220\n    sk_alloc+0x35/0xa00\n    inet6_create.part.0+0x303/0x10d0\n    __sock_create+0x248/0x640\n    __sys_socket+0x11b/0x1d0\n\nSince skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST\npackets constructed by GRO, the truesize adjustment is removed.\n\nThe call to skb_release_head_state() must be preserved. As documented in\ncommit cf673ed0e057 (\"net: fix fraglist segmentation reference count\nleak\"), it is still required to correctly drop references to SKB\nextensions that may be overwritten during __copy_skb_header()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-09T08:36:29.263Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0b27828ebd1ed3107d7929c3737adbe862e99e74"
        },
        {
          "url": "https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab"
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        {
          "url": "https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77"
        }
      ],
      "title": "net: fix memory leak in skb_segment_list for GRO packets",
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-22979",
    "datePublished": "2026-01-23T15:24:01.340Z",
    "dateReserved": "2026-01-13T15:37:45.936Z",
    "dateUpdated": "2026-02-09T08:36:29.263Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-22979\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-23T16:15:53.893\",\"lastModified\":\"2026-01-26T15:03:51.687\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet: fix memory leak in skb_segment_list for GRO packets\\n\\nWhen skb_segment_list() is called during packet forwarding, it handles\\npackets that were aggregated by the GRO engine.\\n\\nHistorically, the segmentation logic in skb_segment_list assumes that\\nindividual segments are split from a parent SKB and may need to carry\\ntheir own socket memory accounting. Accordingly, the code transfers\\ntruesize from the parent to the newly created segments.\\n\\nPrior to commit ed4cccef64c1 (\\\"gro: fix ownership transfer\\\"), this\\ntruesize subtraction in skb_segment_list() was valid because fragments\\nstill carry a reference to the original socket.\\n\\nHowever, commit ed4cccef64c1 (\\\"gro: fix ownership transfer\\\") changed\\nthis behavior by ensuring that fraglist entries are explicitly\\norphaned (skb-\u003esk = NULL) to prevent illegal orphaning later in the\\nstack. This change meant that the entire socket memory charge remained\\nwith the head SKB, but the corresponding accounting logic in\\nskb_segment_list() was never updated.\\n\\nAs a result, the current code unconditionally adds each fragment\u0027s\\ntruesize to delta_truesize and subtracts it from the parent SKB. Since\\nthe fragments are no longer charged to the socket, this subtraction\\nresults in an effective under-count of memory when the head is freed.\\nThis causes sk_wmem_alloc to remain non-zero, preventing socket\\ndestruction and leading to a persistent memory leak.\\n\\nThe leak can be observed via KMEMLEAK when tearing down the networking\\nenvironment:\\n\\nunreferenced object 0xffff8881e6eb9100 (size 2048):\\n  comm \\\"ping\\\", pid 6720, jiffies 4295492526\\n  backtrace:\\n    kmem_cache_alloc_noprof+0x5c6/0x800\\n    sk_prot_alloc+0x5b/0x220\\n    sk_alloc+0x35/0xa00\\n    inet6_create.part.0+0x303/0x10d0\\n    __sock_create+0x248/0x640\\n    __sys_socket+0x11b/0x1d0\\n\\nSince skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST\\npackets constructed by GRO, the truesize adjustment is removed.\\n\\nThe call to skb_release_head_state() must be preserved. As documented in\\ncommit cf673ed0e057 (\\\"net: fix fraglist segmentation reference count\\nleak\\\"), it is still required to correctly drop references to SKB\\nextensions that may be overwritten during __copy_skb_header().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0b27828ebd1ed3107d7929c3737adbe862e99e74\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/238e03d0466239410b72294b79494e43d4fabe77\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3264881431e308b9c72cb8a0159d57a56d67dd79\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/88bea149db2057112af3aaf63534b24fab5858ab\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c114a32a2e70b82d447f409f7ffcfa3058f9d5bd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • 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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