{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-74563", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-74563" ], "published": "2026-08-15T12:28:42Z", "summary": "rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()", "details": "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)", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.183", "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-74563" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f8a8977af2134a1d91e5f9773cb7d9d53278c830" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ba95bce5dfe6e2ef602a87e0557225f2934ccb5c" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c4933624a6f416ecfcc31ab58d585da1207a0597" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/76dd48886eeeb5fcf2b837d2f4c3d17eebeac9ef" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f0d1fb05d70c8a561cd8d0473bcacafa2fc137ff" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b1d480fce05f857dc438080cd8c9244b84a83494" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/8398bc477d3cb3e2b018a5aaac2bec0f69acda30" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/78f75d632f74b8de0f081a128588f7c37d0d1164" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-19T16:47:12Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "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()->rds_bind()->rds_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." } } }