{ "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" } } } }