{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68290","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-30T09:28:09.380Z","datePublished":"2026-08-10T12:02:23.425Z","dateUpdated":"2026-08-17T05:02:25.806Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-17T05:02:25.806Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nrds: tcp: unregister sysctl before tearing down listen socket\n\nrds_tcp_exit_net() frees the per-netns RDS TCP listen socket via\nrds_tcp_kill_sock() before unregistering the per-netns sysctl table.  Since\nrds_tcp_skbuf_handler() derives the netns from\nrtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with\nnetns teardown and dereference the freed socket/sk.\n\nKASAN reports the race as:\n\n  BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0\n  rds_tcp_skbuf_handler              net/rds/tcp.c:721\n  proc_sys_call_handler              fs/proc/proc_sysctl.c\n  vfs_write                          fs/read_write.c\n  __x64_sys_pwrite64                 fs/read_write.c\n\nFix this by unregistering the RDS TCP sysctl table before calling\nrds_tcp_kill_sock().  unregister_net_sysctl_table() prevents new sysctl\nhandlers from starting and waits for in-flight handlers to finish, so\nthe listen socket can then be released safely. The fix was tested\nagainst the linked reproducer."}],"metrics":[{"cvssV3_1":{"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"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is triggered by a local write() /pwrite64() to the per-netns sysctl file /proc/sys/net/rds/tcp/rds_tcp_{snd,rcv}buf racing with network namespace teardown; no network traffic reaches the vulnerable handler, so local syscall access is required.\nAC:L - Although this is a race, the attacker controls both sides: they create the netns, keep the sysctl fd open, choose when the netns is destroyed, and issue the concurrent sysctl write in a tight loop, so the race can be retried indefinitely until won.\nPR:L - Only an unprivileged local account is needed: unshare -Urn yields CAP_NET_ADMIN over the new netns's user_ns, and net_ctl_permissions()/net_ctl_set_ownership() then grant that user write access to the RDS TCP sysctls, while the rds_tcp module is autoloaded by an unprivileged AF_RDS socket.\nUI:N - The attacker performs every step itself — namespace creation, opening the sysctl file, triggering teardown and writing — with no action required from any other user or administrator.\nS:U - The use-after-free occurs on kernel slab objects belonging to the same kernel security authority; there is no crossing of a VM, IOMMU or other security boundary.\nC:H - The handler reads the freed listen socket and then dereferences lsock->sk and sock_net(sk); by spraying the freed socket/sk slabs the attacker can steer these dereferences to chosen addresses, turning the use-after-free read into a kernel memory disclosure primitive.\nI:H - Reallocating the freed struct socket/sk with attacker-controlled data lets the attacker supply a bogus struct net pointer that drives rds_tcp_sysctl_reset()/rds_conn_path_drop() over the global RDS connection list, corrupting kernel state and giving the usual UAF path toward control-flow hijack.\nA:H - The confirmed KASAN slab-use-after-free on the freed listen socket readily oopses or panics the kernel, and the race can be repeated by an unprivileged user until it hits, giving a reliable denial of service."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"],"versions":[{"version":"de8d6de0ee27be4b2b1e5b06f04aeacbabbba492","lessThan":"80fffed08dc1c10e971066941d2daa56253f1552","status":"affected","versionType":"git"},{"version":"7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c","lessThan":"16df2d154ec82e2f7e7585b4fa154751ba37729a","status":"affected","versionType":"git"},{"version":"7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c","lessThan":"3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d","status":"affected","versionType":"git"},{"version":"7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c","lessThan":"167e54c703ccd4fa028feb568b0d1002020cff86","status":"affected","versionType":"git"},{"version":"6.12.10","lessThan":"6.12.101","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"],"versions":[{"version":"6.13","status":"affected"},{"version":"0","lessThan":"6.13","status":"unaffected","versionType":"semver"},{"version":"6.12.101","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.42","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.6","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.10","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/80fffed08dc1c10e971066941d2daa56253f1552"},{"url":"https://git.kernel.org/stable/c/16df2d154ec82e2f7e7585b4fa154751ba37729a"},{"url":"https://git.kernel.org/stable/c/3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d"},{"url":"https://git.kernel.org/stable/c/167e54c703ccd4fa028feb568b0d1002020cff86"}],"title":"rds: tcp: unregister sysctl before tearing down listen socket","x_generator":{"engine":"bippy-1.2.0"}}}}