Vulnerability-Lookup

GHSA-2J2R-FXQG-MC3V

Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

ipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings()

syzbot reported a null-ptr-deref in __ip6_del_rt_siblings() [0].

The stack trace hinted towards a null dereference of rt->fib6_node when fn->leaf is accessed in __ip6_del_rt_siblings(). With RTNL_FLAG_DOIT_UNLOCKED set, inet6_rtm_delroute() operations run concurrently without acquiring the RTNL lock. In ip6_route_del(), the route lookup happens under rcu_read_lock() without acquiring table->tb6_lock.

Between ip6_route_del() looking up the route and __ip6_del_rt_siblings() acquiring table->tb6_lock, another thread can modify the routing table. For example, when an ECMP route is replaced via RTM_NEWROUTE with NLM_F_REPLACE, fib6_add_rt2node() unlinks all old siblings and sets iter->fib6_node = NULL. A reproducer was found that triggers this [1].

Add a check to ensure rt->fib6_node is non-null before accessing it.

[0] KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] RIP: 0010:__ip6_del_rt_siblings+0x31e/0x7c0 net/ipv6/route.c:4056 Call Trace: ip6_route_del+0x1054/0x1110 net/ipv6/route.c:4232 inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5669 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] _syssendmsg+0x565/0x870 net/socket.c:2713 _sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f

[1] https://gist.github.com/NamanGulati/0766a1159b6ca61928faaf87425ff899

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{
  "affected": [],
  "aliases": [
    "CVE-2026-97974"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-25T11:17:25Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings()\n\nsyzbot reported a null-ptr-deref in __ip6_del_rt_siblings() [0].\n\nThe stack trace hinted towards a null dereference of rt-\u003efib6_node when\nfn-\u003eleaf is accessed in __ip6_del_rt_siblings(). With\nRTNL_FLAG_DOIT_UNLOCKED set, inet6_rtm_delroute() operations run\nconcurrently without acquiring the RTNL lock. In ip6_route_del(), the\nroute lookup happens under rcu_read_lock() without acquiring\ntable-\u003etb6_lock.\n\nBetween ip6_route_del() looking up the route and __ip6_del_rt_siblings()\nacquiring table-\u003etb6_lock, another thread can modify the routing table.\nFor example, when an ECMP route is replaced via RTM_NEWROUTE with\nNLM_F_REPLACE, fib6_add_rt2node() unlinks all old siblings and sets\niter-\u003efib6_node = NULL. A reproducer was found that triggers this [1].\n\nAdd a check to ensure rt-\u003efib6_node is non-null before accessing it.\n\n[0]\nKASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]\nRIP: 0010:__ip6_del_rt_siblings+0x31e/0x7c0 net/ipv6/route.c:4056\nCall Trace:\n \u003cTASK\u003e\n ip6_route_del+0x1054/0x1110 net/ipv6/route.c:4232\n inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5669\n rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132\n netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556\n netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]\n netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345\n netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900\n sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800\n __sock_sendmsg net/socket.c:815 [inline]\n ____sys_sendmsg+0x565/0x870 net/socket.c:2713\n ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767\n __sys_sendmsg net/socket.c:2799 [inline]\n __do_sys_sendmsg net/socket.c:2804 [inline]\n __se_sys_sendmsg net/socket.c:2802 [inline]\n __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802\n do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]\n do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\n[1] https://gist.github.com/NamanGulati/0766a1159b6ca61928faaf87425ff899",
  "id": "GHSA-2j2r-fxqg-mc3v",
  "modified": "2026-09-25T12:31:31Z",
  "published": "2026-09-25T12:31:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97974"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1155234c2227cf36072a43e1e09119472ade7ca7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cdca92eddc025fdb90071be97738f7d55a65f8dd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e7ff91f19c1aae039a4257fa86fe849afe185291"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-97974 (GCVE-0-2026-97974)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:23 – Updated: 2026-09-25 10:23

Title

ipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings()

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings() syzbot reported a null-ptr-deref in __ip6_del_rt_siblings() [0]. The stack trace hinted towards a null dereference of rt->fib6_node when fn->leaf is accessed in __ip6_del_rt_siblings(). With RTNL_FLAG_DOIT_UNLOCKED set, inet6_rtm_delroute() operations run concurrently without acquiring the RTNL lock. In ip6_route_del(), the route lookup happens under rcu_read_lock() without acquiring table->tb6_lock. Between ip6_route_del() looking up the route and __ip6_del_rt_siblings() acquiring table->tb6_lock, another thread can modify the routing table. For example, when an ECMP route is replaced via RTM_NEWROUTE with NLM_F_REPLACE, fib6_add_rt2node() unlinks all old siblings and sets iter->fib6_node = NULL. A reproducer was found that triggers this [1]. Add a check to ensure rt->fib6_node is non-null before accessing it. [0] KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] RIP: 0010:__ip6_del_rt_siblings+0x31e/0x7c0 net/ipv6/route.c:4056 Call Trace: <TASK> ip6_route_del+0x1054/0x1110 net/ipv6/route.c:4232 inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5669 rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132 netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800 __sock_sendmsg net/socket.c:815 [inline] ____sys_sendmsg+0x565/0x870 net/socket.c:2713 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767 __sys_sendmsg net/socket.c:2799 [inline] __do_sys_sendmsg net/socket.c:2804 [inline] __se_sys_sendmsg net/socket.c:2802 [inline] __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> [1] https://gist.github.com/NamanGulati/0766a1159b6ca61928faaf87425ff899

Severity

No CVSS data available.

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/e7ff91f19c1aae039…
https://git.kernel.org/stable/c/1155234c2227cf360…
https://git.kernel.org/stable/c/cdca92eddc025fdb9…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: bd11ff421d36abdb585b9104fa70057bf01b3110 , < e7ff91f19c1aae039a4257fa86fe849afe185291 (git) Affected: bd11ff421d36abdb585b9104fa70057bf01b3110 , < 1155234c2227cf36072a43e1e09119472ade7ca7 (git) Affected: bd11ff421d36abdb585b9104fa70057bf01b3110 , < cdca92eddc025fdb90071be97738f7d55a65f8dd (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.53 , ≤ 6.18.* (semver) Unaffected: 7.2.7 , ≤ 7.2.* (semver) Unaffected: 7.3-rc3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e7ff91f19c1aae039a4257fa86fe849afe185291",
              "status": "affected",
              "version": "bd11ff421d36abdb585b9104fa70057bf01b3110",
              "versionType": "git"
            },
            {
              "lessThan": "1155234c2227cf36072a43e1e09119472ade7ca7",
              "status": "affected",
              "version": "bd11ff421d36abdb585b9104fa70057bf01b3110",
              "versionType": "git"
            },
            {
              "lessThan": "cdca92eddc025fdb90071be97738f7d55a65f8dd",
              "status": "affected",
              "version": "bd11ff421d36abdb585b9104fa70057bf01b3110",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/route.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.7",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc3",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings()\n\nsyzbot reported a null-ptr-deref in __ip6_del_rt_siblings() [0].\n\nThe stack trace hinted towards a null dereference of rt-\u003efib6_node when\nfn-\u003eleaf is accessed in __ip6_del_rt_siblings(). With\nRTNL_FLAG_DOIT_UNLOCKED set, inet6_rtm_delroute() operations run\nconcurrently without acquiring the RTNL lock. In ip6_route_del(), the\nroute lookup happens under rcu_read_lock() without acquiring\ntable-\u003etb6_lock.\n\nBetween ip6_route_del() looking up the route and __ip6_del_rt_siblings()\nacquiring table-\u003etb6_lock, another thread can modify the routing table.\nFor example, when an ECMP route is replaced via RTM_NEWROUTE with\nNLM_F_REPLACE, fib6_add_rt2node() unlinks all old siblings and sets\niter-\u003efib6_node = NULL. A reproducer was found that triggers this [1].\n\nAdd a check to ensure rt-\u003efib6_node is non-null before accessing it.\n\n[0]\nKASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027]\nRIP: 0010:__ip6_del_rt_siblings+0x31e/0x7c0 net/ipv6/route.c:4056\nCall Trace:\n \u003cTASK\u003e\n ip6_route_del+0x1054/0x1110 net/ipv6/route.c:4232\n inet6_rtm_delroute+0x5d7/0x6d0 net/ipv6/route.c:5669\n rtnetlink_rcv_msg+0x802/0xc00 net/core/rtnetlink.c:7132\n netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556\n netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]\n netlink_unicast+0x7f5/0x990 net/netlink/af_netlink.c:1345\n netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900\n sock_sendmsg_nosec+0x13a/0x180 net/socket.c:800\n __sock_sendmsg net/socket.c:815 [inline]\n ____sys_sendmsg+0x565/0x870 net/socket.c:2713\n ___sys_sendmsg+0x2a5/0x360 net/socket.c:2767\n __sys_sendmsg net/socket.c:2799 [inline]\n __do_sys_sendmsg net/socket.c:2804 [inline]\n __se_sys_sendmsg net/socket.c:2802 [inline]\n __x64_sys_sendmsg+0x1b7/0x290 net/socket.c:2802\n do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]\n do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n \u003c/TASK\u003e\n\n[1] https://gist.github.com/NamanGulati/0766a1159b6ca61928faaf87425ff899"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T10:23:13.373Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e7ff91f19c1aae039a4257fa86fe849afe185291"
        },
        {
          "url": "https://git.kernel.org/stable/c/1155234c2227cf36072a43e1e09119472ade7ca7"
        },
        {
          "url": "https://git.kernel.org/stable/c/cdca92eddc025fdb90071be97738f7d55a65f8dd"
        }
      ],
      "title": "ipv6: null-check fib6_node before accessing in __ip6_del_rt_siblings()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-97974",
    "datePublished": "2026-09-25T10:23:13.373Z",
    "dateReserved": "2026-09-25T10:18:58.207Z",
    "dateUpdated": "2026-09-25T10:23:13.373Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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GHSA-2J2R-FXQG-MC3V

CVE-2026-97974 (GCVE-0-2026-97974)

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