{"id":"CVE-2026-68335","title":"rds: drop incoming messages that cross network namespace boundaries","summary":"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, p…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 742ff6f02545212e991cd8b45011e40d2c2ef25a","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < abff41fd928328bbf3dda1140beb2e61fa424ccd","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 03c574112e5d066df0ddce36d7438e850bcf3050","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 1e2e2d9806944fe485824d617c8b7c78116c22db","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < cfb3ce07b705e486e022a2f2b1242b48f13981ff","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 9591042533140dfe6608d9344806d567dcd39d02","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 0f8690e3869109cd5803ccb400889d20a0b54e0e","Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 5521ae71e32a8069ed4ca6e792179dc57bc43ab2","Linux c827073c95fde388bc65fe5227f944eaf859b9f0","Linux >= 4.17.19 < 4.18","Linux 4.18"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:47:14.247347Z"},"published":"2026-08-10","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:53:08.546Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-68335","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"}],"tags":["cve.org"],"epss":0.00135,"epssPercentile":0.02628,"ingestedAt":"2026-10-16T17:24:46.858Z","slug":"CVE-2026-68335","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 742ff6f02545212e991cd8b45011e40d2c2ef25a`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < abff41fd928328bbf3dda1140beb2e61fa424ccd`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 03c574112e5d066df0ddce36d7438e850bcf3050`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 1e2e2d9806944fe485824d617c8b7c78116c22db`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < cfb3ce07b705e486e022a2f2b1242b48f13981ff`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 9591042533140dfe6608d9344806d567dcd39d02`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 0f8690e3869109cd5803ccb400889d20a0b54e0e`\n- `Linux >= c809195f5523dd4d09403bbb1c9732d548aa0d1e < 5521ae71e32a8069ed4ca6e792179dc57bc43ab2`\n- `Linux c827073c95fde388bc65fe5227f944eaf859b9f0`\n- `Linux >= 4.17.19 < 4.18`\n- `Linux 4.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}