CVE-2026-74563 (GCVE-0-2026-74563)

Vulnerability from cvelistv5 – Published: 2026-08-15 12:28 – Updated: 2026-08-17 05:48
VLAI
Title
rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()
Summary
In the Linux kernel, the following vulnerability has been resolved: rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check() rds_tcp_laddr_check() looks up a scoped IPv6 interface with dev_get_by_index_rcu(), drops the RCU read-side lock, and only then passes the bare struct net_device * into ipv6_chk_addr(). dev_get_by_index_rcu() only keeps the device alive within the same RCU read-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can free the net_device; ipv6_chk_addr() then dereferences the stale pointer in __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading freed memory. Keep the RCU read-side lock held across the ipv6_chk_addr() call instead of dropping it right after the lookup, so the device cannot be freed while it is in use. BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998) Read of size 8 at addr ffff8880106ec000 by task exploit/153 Call Trace: ... kasan_report (mm/kasan/report.c:595) __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998) ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972) rds_tcp_laddr_check (net/rds/tcp.c:370) rds_bind (net/rds/bind.c:248) __sys_bind (net/socket.c:1920) __x64_sys_bind (net/socket.c:1956) do_syscall_64 (arch/x86/entry/syscall_64.c:63) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 , < 76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef (git)
Affected: eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 , < f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff (git)
Affected: eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 , < b1d480fce05f857dc438080cd8c9244b84a83494 (git)
Affected: eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 , < 8398bc477d3cb3e2b018a5aaac2bec0f69acda30 (git)
Affected: eee2fa6ab3225192d6d894c54a6fb02ac9efdff6 , < 78f75d632f74b8de0f081a128588f7c37d0d1164 (git)
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Linux Linux Affected: 4.19
Unaffected: 0 , < 4.19 (semver)
Unaffected: 6.6.151 , ≤ 6.6.* (semver)
Unaffected: 6.12.103 , ≤ 6.12.* (semver)
Unaffected: 6.18.44 , ≤ 6.18.* (semver)
Unaffected: 7.1.8 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/rds/tcp.c"
          ],
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.151",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.8",
                  "versionStartIncluding": "4.19",
                  "vulnerable": true
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                  "versionEndExcluding": "7.2",
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                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()\n\nrds_tcp_laddr_check() looks up a scoped IPv6 interface with\ndev_get_by_index_rcu(), drops the RCU read-side lock, and only then\npasses the bare struct net_device * into ipv6_chk_addr().\n\ndev_get_by_index_rcu() only keeps the device alive within the same RCU\nread-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can\nfree the net_device; ipv6_chk_addr() then dereferences the stale pointer\nin __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading\nfreed memory.\n\nKeep the RCU read-side lock held across the ipv6_chk_addr() call instead\nof dropping it right after the lookup, so the device cannot be freed\nwhile it is in use.\n\n  BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)\n  Read of size 8 at addr ffff8880106ec000 by task exploit/153\n  Call Trace:\n   ...\n   kasan_report (mm/kasan/report.c:595)\n   __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)\n   ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972)\n   rds_tcp_laddr_check (net/rds/tcp.c:370)\n   rds_bind (net/rds/bind.c:248)\n   __sys_bind (net/socket.c:1920)\n   __x64_sys_bind (net/socket.c:1956)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:63)\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)"
        }
      ],
      "metrics": [
        {
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            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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            {
              "lang": "en",
              "value": "AV:L - The slab use-after-free is reached via the bind(2) syscall on an AF_RDS socket with a link-local IPv6 address and non-zero scope_id; the KASAN reproducer follows bind()-\u003erds_bind()-\u003erds_tcp_laddr_check(), requiring on-host access to race bind against RTM_DELLINK netlink deletion of the referenced netdev.\nAC:L - Exploitation requires racing rds_tcp_laddr_check() against RTM_DELLINK freeing the netdev; the attacker controls both sides by concurrently calling bind() and deleting the interface via netlink (e.g., a veth in a user namespace) and can retry until the race succeeds.\nPR:L - An unprivileged local user can create AF_RDS sockets and call bind(); the RTM_DELLINK race is achievable with CAP_NET_ADMIN obtainable inside an unprivileged user+network namespace (unshare -Urn), not requiring init-namespace root.\nUI:N - No victim interaction is required; exploitation is fully attacker-driven through bind/netlink syscalls without needing another user to mount a filesystem, click, or open a file.\nS:U - Impact is confined to kernel memory corruption and potential privilege escalation within the same kernel/host security boundary; this is not a VM-guest-to-host escape, sandbox escape, or cross-authority boundary crossing.\nC:H - The bug is a slab use-after-free read of a freed struct net_device in __ipv6_chk_addr_and_flags() via a stale pointer passed to ipv6_chk_addr(); UAF reads of kernel heap objects can disclose sensitive memory and enable further exploitation.\nI:H - Use-after-free on struct net_device heap memory provides memory corruption primitives that can be groomed for arbitrary kernel writes, control-flow hijacking, and local privilege escalation, not merely a bounded or transient error.\nA:H - The reported KASAN slab-use-after-free causes kernel oops/panic during the stale dereference in the IPv6 address-check path; UAF conditions are inherently crash-prone even when not fully weaponized for code execution."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:48:43.058Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/78f75d632f74b8de0f081a128588f7c37d0d1164"
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      ],
      "title": "rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74563",
    "datePublished": "2026-08-15T12:28:05.768Z",
    "dateReserved": "2026-08-15T05:44:03.916Z",
    "dateUpdated": "2026-08-17T05:48:43.058Z",
    "state": "PUBLISHED"
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After rcu_read_unlock(), a concurrent RTM_DELLINK can\\nfree the net_device; ipv6_chk_addr() then dereferences the stale pointer\\nin __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading\\nfreed memory.\\n\\nKeep the RCU read-side lock held across the ipv6_chk_addr() call instead\\nof dropping it right after the lookup, so the device cannot be freed\\nwhile it is in use.\\n\\n  BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)\\n  Read of size 8 at addr ffff8880106ec000 by task exploit/153\\n  Call Trace:\\n   ...\\n   kasan_report (mm/kasan/report.c:595)\\n   __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)\\n   ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972)\\n   rds_tcp_laddr_check (net/rds/tcp.c:370)\\n   rds_bind (net/rds/bind.c:248)\\n   __sys_bind (net/socket.c:1920)\\n   __x64_sys_bind (net/socket.c:1956)\\n   do_syscall_64 (arch/x86/entry/syscall_64.c:63)\\n   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/rds/tcp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"eee2fa6ab3225192d6d894c54a6fb02ac9efdff6\",\"lessThan\":\"76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"eee2fa6ab3225192d6d894c54a6fb02ac9efdff6\",\"lessThan\":\"f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"eee2fa6ab3225192d6d894c54a6fb02ac9efdff6\",\"lessThan\":\"b1d480fce05f857dc438080cd8c9244b84a83494\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"eee2fa6ab3225192d6d894c54a6fb02ac9efdff6\",\"lessThan\":\"8398bc477d3cb3e2b018a5aaac2bec0f69acda30\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"eee2fa6ab3225192d6d894c54a6fb02ac9efdff6\",\"lessThan\":\"78f75d632f74b8de0f081a128588f7c37d0d1164\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/rds/tcp.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.19\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.19\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.151\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.103\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.44\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.8\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/78f75d632f74b8de0f081a128588f7c37d0d1164\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8398bc477d3cb3e2b018a5aaac2bec0f69acda30\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b1d480fce05f857dc438080cd8c9244b84a83494\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "suse_vex": {
      "aggregate_severity": "not set",
      "current_release_date": "2026-08-15T23:50:08Z",
      "cve": "CVE-2026-74563",
      "id": "CVE-2026-74563",
      "initial_release_date": "2026-08-15T23:50:08Z",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74563",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74563.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.


Detection rules are retrieved from Rulezet.