{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-68335", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-30T09:28:09.383Z", "datePublished": "2026-08-10T12:03:11.547Z", "dateUpdated": "2026-08-19T16:33:33.100Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-19T16:33:33.100Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/rds/recv.c" ], "versions": [ { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "742ff6f02545212e991cd8b45011e40d2c2ef25a", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "abff41fd928328bbf3dda1140beb2e61fa424ccd", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "03c574112e5d066df0ddce36d7438e850bcf3050", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "1e2e2d9806944fe485824d617c8b7c78116c22db", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "cfb3ce07b705e486e022a2f2b1242b48f13981ff", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "9591042533140dfe6608d9344806d567dcd39d02", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "0f8690e3869109cd5803ccb400889d20a0b54e0e", "status": "affected", "versionType": "git" }, { "version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e", "lessThan": "5521ae71e32a8069ed4ca6e792179dc57bc43ab2", "status": "affected", "versionType": "git" }, { "version": "c827073c95fde388bc65fe5227f944eaf859b9f0", "status": "affected", "versionType": "git" }, { "version": "4.17.19", "lessThan": "4.18", "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/recv.c" ], "versions": [ { "version": "4.18", "status": "affected" }, { "version": "0", "lessThan": "4.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.265", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.216", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.183", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.148", "lessThanOrEqual": "6.6.*", "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": "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" } ] } ] } ], "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" } ], "title": "rds: drop incoming messages that cross network namespace boundaries", "x_generator": { "engine": "bippy-1.2.0" } } } }