{"id":"CVE-2026-68335","state":"PUBLISHED","title":"rds: drop incoming messages that cross network namespace boundaries","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nrds: drop incoming messages that cross network namespace boundaries\n\nrds_find_bound() looks up the destination socket using a global\nrhashtable keyed solely on (addr, port, scope_id).  Network namespaces\nare not part of the key, so a sender in netns A can deliver an incoming\nmessage (inc) to a socket that lives in a different netns B.\n\nWhen this happens, inc->i_conn points to an rds_connection whose c_net\nis netns A, but the receiving rs lives in netns B.  Once the child\nprocess that created netns A exits, cleanup_net() calls\nrds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(),\nfreeing that connection.  If the survivor socket in netns B still holds\nthe inc, any subsequent dereference of inc->i_conn is a use-after-free.\n\nThere are two dangerous sites in rds_clear_recv_queue():\n  1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200)\n     read via rds_recv_rcvbuf_delta() -- confirmed by KASAN.\n  2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80)\n     called via rds_inc_put() when the inc refcount reaches zero -- same\n     race window, potential call-through-freed-object primitive.\n\nThe bug is reachable from unprivileged user namespaces\n(CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8.\n\nFix this by rejecting the delivery in rds_recv_incoming() when the\nsocket returned by rds_find_bound() belongs to a different network\nnamespace than the connection that carried the message.  Use the\nexisting rds_conn_net() / sock_net() helpers and net_eq() for the\ncomparison.","publishedAt":"2026-08-10T12:03:11.547Z","updatedAt":"2026-10-19T21:09:05.269Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"742ff6f02545212e991cd8b45011e40d2c2ef25a","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"abff41fd928328bbf3dda1140beb2e61fa424ccd","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"03c574112e5d066df0ddce36d7438e850bcf3050","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"1e2e2d9806944fe485824d617c8b7c78116c22db","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"cfb3ce07b705e486e022a2f2b1242b48f13981ff","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"9591042533140dfe6608d9344806d567dcd39d02","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"0f8690e3869109cd5803ccb400889d20a0b54e0e","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"5521ae71e32a8069ed4ca6e792179dc57bc43ab2","versionType":"git"},{"version":"c827073c95fde388bc65fe5227f944eaf859b9f0","status":"affected","versionType":"git"},{"version":"4.17.19","status":"affected","lessThan":"4.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/recv.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.18","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/recv.c"]}],"references":["https://git.kernel.org/stable/c/742ff6f02545212e991cd8b45011e40d2c2ef25a","https://git.kernel.org/stable/c/abff41fd928328bbf3dda1140beb2e61fa424ccd","https://git.kernel.org/stable/c/03c574112e5d066df0ddce36d7438e850bcf3050","https://git.kernel.org/stable/c/1e2e2d9806944fe485824d617c8b7c78116c22db","https://git.kernel.org/stable/c/cfb3ce07b705e486e022a2f2b1242b48f13981ff","https://git.kernel.org/stable/c/9591042533140dfe6608d9344806d567dcd39d02","https://git.kernel.org/stable/c/0f8690e3869109cd5803ccb400889d20a0b54e0e","https://git.kernel.org/stable/c/5521ae71e32a8069ed4ca6e792179dc57bc43ab2"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/68xxx/CVE-2026-68335.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-68335","state":"PUBLISHED","datePublished":"2026-08-10T12:03:11.547Z","dateUpdated":"2026-10-19T21:09:05.269Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-30T09:28:09.383Z"},"containers":{"cna":{"title":"rds: drop incoming messages that cross network namespace boundaries","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nrds: drop incoming messages that cross network namespace boundaries\n\nrds_find_bound() looks up the destination socket using a global\nrhashtable keyed solely on (addr, port, scope_id).  Network namespaces\nare not part of the key, so a sender in netns A can deliver an incoming\nmessage (inc) to a socket that lives in a different netns B.\n\nWhen this happens, inc->i_conn points to an rds_connection whose c_net\nis netns A, but the receiving rs lives in netns B.  Once the child\nprocess that created netns A exits, cleanup_net() calls\nrds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(),\nfreeing that connection.  If the survivor socket in netns B still holds\nthe inc, any subsequent dereference of inc->i_conn is a use-after-free.\n\nThere are two dangerous sites in rds_clear_recv_queue():\n  1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200)\n     read via rds_recv_rcvbuf_delta() -- confirmed by KASAN.\n  2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80)\n     called via rds_inc_put() when the inc refcount reaches zero -- same\n     race window, potential call-through-freed-object primitive.\n\nThe bug is reachable from unprivileged user namespaces\n(CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8.\n\nFix this by rejecting the delivery in rds_recv_incoming() when the\nsocket returned by rds_find_bound() belongs to a different network\nnamespace than the connection that carried the message.  Use the\nexisting rds_conn_net() / sock_net() helpers and net_eq() for the\ncomparison."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"742ff6f02545212e991cd8b45011e40d2c2ef25a","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"abff41fd928328bbf3dda1140beb2e61fa424ccd","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"03c574112e5d066df0ddce36d7438e850bcf3050","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"1e2e2d9806944fe485824d617c8b7c78116c22db","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"cfb3ce07b705e486e022a2f2b1242b48f13981ff","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"9591042533140dfe6608d9344806d567dcd39d02","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"0f8690e3869109cd5803ccb400889d20a0b54e0e","versionType":"git"},{"version":"c809195f5523dd4d09403bbb1c9732d548aa0d1e","status":"affected","lessThan":"5521ae71e32a8069ed4ca6e792179dc57bc43ab2","versionType":"git"},{"version":"c827073c95fde388bc65fe5227f944eaf859b9f0","status":"affected","versionType":"git"},{"version":"4.17.19","status":"affected","lessThan":"4.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/recv.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.18","versionType":"semver"},{"version":"5.10.265","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.216","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.183","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.148","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.101","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.42","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.6","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/recv.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/742ff6f02545212e991cd8b45011e40d2c2ef25a"},{"url":"https://git.kernel.org/stable/c/abff41fd928328bbf3dda1140beb2e61fa424ccd"},{"url":"https://git.kernel.org/stable/c/03c574112e5d066df0ddce36d7438e850bcf3050"},{"url":"https://git.kernel.org/stable/c/1e2e2d9806944fe485824d617c8b7c78116c22db"},{"url":"https://git.kernel.org/stable/c/cfb3ce07b705e486e022a2f2b1242b48f13981ff"},{"url":"https://git.kernel.org/stable/c/9591042533140dfe6608d9344806d567dcd39d02"},{"url":"https://git.kernel.org/stable/c/0f8690e3869109cd5803ccb400889d20a0b54e0e"},{"url":"https://git.kernel.org/stable/c/5521ae71e32a8069ed4ca6e792179dc57bc43ab2"}],"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 - Exploitation requires local syscall access: the attacker must create RDS sockets and a network namespace (CLONE_NEWUSER|CLONE_NEWNET), then trigger namespace teardown to free the connection. A remote RDS peer cannot drive the netns-destruction half of the sequence, so the vulnerability is reachable only locally.\nAC:L - The attacker controls the entire sequence deterministically — bind a socket in one netns, send a loopback RDS message from a second netns so the inc is queued cross-netns, then exit that netns to free inc->i_conn. No race must be won and no uncontrollable precondition exists; the UAF is confirmed reproducible under KASAN.\nPR:L - Only an unprivileged local user account is required; the needed CAP_NET_ADMIN for creating and configuring the second network namespace is obtained inside a user namespace the attacker owns, as the commit explicitly notes (\"reachable from unprivileged user namespaces\").\nUI:N - The attacker performs every step — socket creation, cross-netns send, namespace teardown, and the subsequent read/close that dereferences the freed connection — with no action from any other user or administrator.\nS:U - The use-after-free corrupts kernel memory within the same kernel security authority; there is no crossing of a hypervisor, IOMMU, or comparable trust boundary.\nC:H - The stale inc->i_conn is dereferenced to read c_lcong from a freed 200-byte rds_connection, and the freed slot can be reclaimed with attacker-groomed data, giving a use-after-free read primitive usable to disclose kernel memory contents.\nI:H - rds_inc_put() calls inc->i_conn->c_trans->inc_free(inc) through a function pointer at offset 80 of the freed object — an indirect call through freed memory that the commit calls a \"call-through-freed-object primitive\", which after heap reclamation is a control-flow hijack path leading to arbitrary kernel modification.\nA:H - Dereferencing the freed rds_connection in rds_clear_recv_queue() and calling through its freed transport vtable reliably corrupts kernel state and panics the machine (KASAN-confirmed use-after-free), causing a full denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-19T16:33:33.100Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.12.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"6.18.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"7.1.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.18","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.17.19"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-68335","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:47:14.247347Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","lang":"en","type":"CWE","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T21:09:05.269Z"}}]}}}