CVE-2026-97958 (GCVE-0-2026-97958)
Vulnerability from cvelistv5
Published
2026-09-25 10:23
Modified
2026-10-19 09:11
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: Don't replay RTM_GETCHAIN in tc_ctl_chain(). If a netlink socket sends RTM_GETCHAIN requests repeatedly without recv()ing the responses, tc_ctl_chain() hogs CPU and triggers Hung Task splat. [0] As caught in the stack trace, netlink_attachskb() could confuse tc_ctl_chain() by returning -EAGAIN when the userspace netlink socket's receive buffer is full. The replay: label exists since commit 32a4f5ecd738 ("net: sched: introduce chain object to uapi") but was not used initially. Since commit 9f407f1768d3 ("net: sched: introduce chain templates"), the label is needed for RTM_NEWCHAIN because tcf_proto_lookup_ops() may release RTNL to call request_module(). However, the replay logic is unnecessary for RTM_GETCHAIN. Let's apply the replay logic only for RTM_NEWCHAIN. [0]: INFO: task repro:1018 is blocked on a mutex likely owned by task repro:1022. task:repro state:R running task stack:14096 pid:1022 tgid:1014 ppid:961 task_flags:0x400040 flags:0x00080000 Call Trace: <TASK> ? clockevents_program_event (kernel/time/clockevents.c:372) ? pskb_expand_head (net/core/skbuff.c:615) ? skb_release_data (net/core/skbuff.c:1122) ? netlink_attachskb (./include/linux/skbuff.h:1323 ./include/linux/skbuff.h:1332 net/netlink/af_netlink.c:1232) ? __netlink_lookup (./include/linux/rcupdate.h:882 ./include/linux/rhashtable.h:711 net/netlink/af_netlink.c:499) ? tc_chain_notify (net/sched/cls_api.c:3045) ? tc_chain_notify (./include/linux/skbuff.h:1384 net/sched/cls_api.c:3041) ? netlink_unicast (net/netlink/af_netlink.c:1335) ? rtnl_unicast (./include/net/netlink.h:1198 net/core/rtnetlink.c:985) ? tc_ctl_chain (net/sched/cls_api.c:3242) ? rtnetlink_rcv_msg (net/core/rtnetlink.c:7146) ? netlink_unicast (net/netlink/af_netlink.c:1354) ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:7177) ? netlink_rcv_skb (net/netlink/af_netlink.c:2556) ? netlink_unicast (net/netlink/af_netlink.c:1319) ? netlink_sendmsg (net/netlink/af_netlink.c:1900) ? __sock_sendmsg (net/socket.c:800) ? __sys_sendto (net/socket.c:2281) ? __x64_sys_sendto (net/socket.c:2288 net/socket.c:2284 net/socket.c:2284) ? do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84) ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK>
References
Impacted products
Vendor Product Version
Linux Linux Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
Version: 2ed9db3074fcd8d12709fe40ff0e691d74229818
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "net/sched/cls_api.c"
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          "vendor": "Linux",
          "versions": [
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_api: Don\u0027t replay RTM_GETCHAIN in tc_ctl_chain().\n\nIf a netlink socket sends RTM_GETCHAIN requests repeatedly\nwithout recv()ing the responses, tc_ctl_chain() hogs CPU and\ntriggers Hung Task splat. [0]\n\nAs caught in the stack trace, netlink_attachskb() could confuse\ntc_ctl_chain() by returning -EAGAIN when the userspace netlink\nsocket\u0027s receive buffer is full.\n\nThe replay: label exists since commit 32a4f5ecd738 (\"net: sched:\nintroduce chain object to uapi\") but was not used initially.\n\nSince commit 9f407f1768d3 (\"net: sched: introduce chain templates\"),\nthe label is needed for RTM_NEWCHAIN because tcf_proto_lookup_ops()\nmay release RTNL to call request_module().\n\nHowever, the replay logic is unnecessary for RTM_GETCHAIN.\n\nLet\u0027s apply the replay logic only for RTM_NEWCHAIN.\n\n[0]:\nINFO: task repro:1018 is blocked on a mutex likely owned by task repro:1022.\ntask:repro           state:R  running task     stack:14096 pid:1022  tgid:1014  ppid:961    task_flags:0x400040 flags:0x00080000\nCall Trace:\n \u003cTASK\u003e\n ? clockevents_program_event (kernel/time/clockevents.c:372)\n ? pskb_expand_head (net/core/skbuff.c:615)\n ? skb_release_data (net/core/skbuff.c:1122)\n ? netlink_attachskb (./include/linux/skbuff.h:1323 ./include/linux/skbuff.h:1332 net/netlink/af_netlink.c:1232)\n ? __netlink_lookup (./include/linux/rcupdate.h:882 ./include/linux/rhashtable.h:711 net/netlink/af_netlink.c:499)\n ? tc_chain_notify (net/sched/cls_api.c:3045)\n ? tc_chain_notify (./include/linux/skbuff.h:1384 net/sched/cls_api.c:3041)\n ? netlink_unicast (net/netlink/af_netlink.c:1335)\n ? rtnl_unicast (./include/net/netlink.h:1198 net/core/rtnetlink.c:985)\n ? tc_ctl_chain (net/sched/cls_api.c:3242)\n ? rtnetlink_rcv_msg (net/core/rtnetlink.c:7146)\n ? netlink_unicast (net/netlink/af_netlink.c:1354)\n ? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:7177)\n ? netlink_rcv_skb (net/netlink/af_netlink.c:2556)\n ? netlink_unicast (net/netlink/af_netlink.c:1319)\n ? netlink_sendmsg (net/netlink/af_netlink.c:1900)\n ? __sock_sendmsg (net/socket.c:800)\n ? __sys_sendto (net/socket.c:2281)\n ? __x64_sys_sendto (net/socket.c:2288 net/socket.c:2284 net/socket.c:2284)\n ? do_syscall_64 (arch/x86/entry/syscall_64.c:61 arch/x86/entry/syscall_64.c:84)\n ? entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:11:24.306Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/240251a4ca7cda213103694b6e21c4a5745e5d8b"
        },
        {
          "url": "https://git.kernel.org/stable/c/9a0f07f7dbd1bfe8c2fd03ad055e9e60a703d5df"
        },
        {
          "url": "https://git.kernel.org/stable/c/6558b0d46c5941ed1aa67da8878e224c54239cc5"
        },
        {
          "url": "https://git.kernel.org/stable/c/96c2fc5daf983af2e0c1256c31e89c1f3f855279"
        },
        {
          "url": "https://git.kernel.org/stable/c/a1c2840d95af1fa3d83ba71e23fa0c674a4c6796"
        },
        {
          "url": "https://git.kernel.org/stable/c/503ba58481e3ba69d28127d35a39cec529f9670c"
        },
        {
          "url": "https://git.kernel.org/stable/c/e9ac395bb56122a057d0aa91a6b55d9e3fa37c26"
        },
        {
          "url": "https://git.kernel.org/stable/c/dff39930ad5e53d202bfdfb14687d1d2fd753b4d"
        }
      ],
      "title": "net/sched: cls_api: Don\u0027t replay RTM_GETCHAIN in tc_ctl_chain().",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97958",
    "datePublished": "2026-09-25T10:23:03.753Z",
    "dateReserved": "2026-09-25T10:18:58.205Z",
    "dateUpdated": "2026-10-19T09:11:24.306Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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