CVE-2026-93226 (GCVE-0-2026-93226)
Vulnerability from cvelistv5
Published
2026-09-24 15:28
Modified
2026-10-19 09:07
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: use RCU iterator to dump route exceptions rt6_nh_dump_exceptions() uses hlist_for_each_entry() to iterate over RCU-protected exception lists. The caller holds rcu_read_lock(), but does not hold rt6_exception_lock, so rt6_insert_exception() can concurrently add an entry with hlist_add_head_rcu(). KCSAN reports this race (irrelevant details omitted): ================================================================== BUG: KCSAN: data-race in rt6_insert_exception / rt6_nh_dump_exceptions write (marked) to 0xffff8a7c44c59620 of 8 bytes by interrupt on cpu 5: rt6_insert_exception+0x3bb/0x760 __ip6_rt_update_pmtu+0x4fe/0x750 ip6_sk_update_pmtu+0x19a/0x3b0 udpv6_err+0x3ff/0x800 icmpv6_notify+0x1e1/0x440 icmpv6_rcv+0x8c0/0xab0 ip6_protocol_deliver_rcu+0x616/0x840 ip6_input_finish+0xb9/0x160 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8a7c44c59620 of 8 bytes by task 549 on cpu 14: rt6_nh_dump_exceptions+0xb3/0x260 rt6_dump_route+0x53e/0x5f0 fib6_dump_node+0x6d/0xf0 fib6_walk_continue+0x290/0x2d0 fib6_dump_table+0x28d/0x360 inet6_dump_fib+0x37d/0x620 rtnl_dumpit+0x7b/0xd0 netlink_dump+0x3ae/0x7e0 ... entry_SYSCALL_64_after_hwframe+0x77/0x7f 4 locks held by dumper/549: ... #1: (rcu_read_lock){....}-{1:3}, at: inet6_dump_fib+0x88/0x620 #2: (&tb->tb6_lock){+.-.}-{3:3}, at: fib6_dump_table+0x1e9/0x360 #3: (rcu_read_lock){....}-{1:3}, at: rt6_dump_route+0x483/0x5f0 value changed: 0xffff8a7c44e05700 -> 0xffff8a7c45d60100 Reported by Kernel Concurrency Sanitizer on: CPU: 14 UID: 0 PID: 549 Comm: dumper Not tainted 7.2.0-rc7-virtme #38 PREEMPT(lazy) ... Use hlist_for_each_entry_rcu() to safely iterate over the exception list.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
Version: 1e47b4837f3bdaa425727cfe09f5ae3b6c4c41a9
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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",
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        },
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.109",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.50",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
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                  "vulnerable": true
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                  "vulnerable": true
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                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "5.3",
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU iterator to dump route exceptions\n\nrt6_nh_dump_exceptions() uses hlist_for_each_entry() to iterate over\nRCU-protected exception lists. The caller holds rcu_read_lock(), but does\nnot hold rt6_exception_lock, so rt6_insert_exception() can concurrently\nadd an entry with hlist_add_head_rcu().\n\nKCSAN reports this race (irrelevant details omitted):\n\n  ==================================================================\n  BUG: KCSAN: data-race in rt6_insert_exception / rt6_nh_dump_exceptions\n\n  write (marked) to 0xffff8a7c44c59620 of 8 bytes by interrupt on cpu 5:\n    rt6_insert_exception+0x3bb/0x760\n    __ip6_rt_update_pmtu+0x4fe/0x750\n    ip6_sk_update_pmtu+0x19a/0x3b0\n    udpv6_err+0x3ff/0x800\n    icmpv6_notify+0x1e1/0x440\n    icmpv6_rcv+0x8c0/0xab0\n    ip6_protocol_deliver_rcu+0x616/0x840\n    ip6_input_finish+0xb9/0x160\n    ...\n    entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n  read to 0xffff8a7c44c59620 of 8 bytes by task 549 on cpu 14:\n    rt6_nh_dump_exceptions+0xb3/0x260\n    rt6_dump_route+0x53e/0x5f0\n    fib6_dump_node+0x6d/0xf0\n    fib6_walk_continue+0x290/0x2d0\n    fib6_dump_table+0x28d/0x360\n    inet6_dump_fib+0x37d/0x620\n    rtnl_dumpit+0x7b/0xd0\n    netlink_dump+0x3ae/0x7e0\n    ...\n    entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n  4 locks held by dumper/549:\n    ...\n    #1: (rcu_read_lock){....}-{1:3}, at: inet6_dump_fib+0x88/0x620\n    #2: (\u0026tb-\u003etb6_lock){+.-.}-{3:3}, at: fib6_dump_table+0x1e9/0x360\n    #3: (rcu_read_lock){....}-{1:3}, at: rt6_dump_route+0x483/0x5f0\n\n  value changed: 0xffff8a7c44e05700 -\u003e 0xffff8a7c45d60100\n\n  Reported by Kernel Concurrency Sanitizer on:\n  CPU: 14 UID: 0 PID: 549 Comm: dumper Not tainted\n  7.2.0-rc7-virtme #38 PREEMPT(lazy)\n  ...\n\nUse hlist_for_each_entry_rcu() to safely iterate over the exception list."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:07:37.714Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/dffbfb3117138e8e0e09d05f507bd36ca1f696e5"
        },
        {
          "url": "https://git.kernel.org/stable/c/6bd3f94ed858f2d072627546b4cdf712b0f8ea88"
        },
        {
          "url": "https://git.kernel.org/stable/c/9c6be625e1a7258e845d6193b3b6b084a00f8e9e"
        },
        {
          "url": "https://git.kernel.org/stable/c/3665abc3d2ae8a78cb67f858e848481432ec75db"
        },
        {
          "url": "https://git.kernel.org/stable/c/eda56ee17713f9dd834b922f7dbfa2e25fa6358c"
        },
        {
          "url": "https://git.kernel.org/stable/c/a602cd128d17a793e12888edc8eda85821ede7e1"
        },
        {
          "url": "https://git.kernel.org/stable/c/f6b1b15848fd91fe122dac0d19d3d666e35075b6"
        },
        {
          "url": "https://git.kernel.org/stable/c/47cdab0d51aaa9bd85f8e4904585bd5bd4df4488"
        }
      ],
      "title": "ipv6: use RCU iterator to dump route exceptions",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93226",
    "datePublished": "2026-09-24T15:28:55.977Z",
    "dateReserved": "2026-09-17T16:02:15.094Z",
    "dateUpdated": "2026-10-19T09:07:37.714Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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