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CVE-2026-68335

rds: drop incoming messages that cross network namespace boundaries PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: rds: drop incoming messages that cross network namespace boundaries rds_find_bound() looks up the destination socket using a global rhashtable keyed solely on (addr, port, scope_id). Network namespaces are not part of the key, so a sender in netns A can deliver an incoming message (inc) to a socket that lives in a different netns B. When this happens, inc->i_conn points to an rds_connection whose c_net is netns A, but the receiving rs lives in netns B. Once the child process that created netns A exits, cleanup_net() calls rds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(), freeing that connection. If the survivor socket in netns B still holds the inc, any subsequent dereference of inc->i_conn is a use-after-free. There are two dangerous sites in rds_clear_recv_queue(): 1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200) read via rds_recv_rcvbuf_delta() -- confirmed by KASAN. 2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80) called via rds_inc_put() when the inc refcount reaches zero -- same race window, potential call-through-freed-object primitive. The bug is reachable from unprivileged user namespaces (CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8. Fix this by rejecting the delivery in rds_recv_incoming() when the socket returned by rds_find_bound() belongs to a different network namespace than the connection that carried the message. Use the existing rds_conn_net() / sock_net() helpers and net_eq() for the comparison.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 742ff6f02545212e991cd8b45011e40d2c2ef25a; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before abff41fd928328bbf3dda1140beb2e61fa424ccd; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 03c574112e5d066df0ddce36d7438e850bcf3050; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 1e2e2d9806944fe485824d617c8b7c78116c22db; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before cfb3ce07b705e486e022a2f2b1242b48f13981ff; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 9591042533140dfe6608d9344806d567dcd39d02; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 0f8690e3869109cd5803ccb400889d20a0b54e0e; affected c809195f5523dd4d09403bbb1c9732d548aa0d1e before 5521ae71e32a8069ed4ca6e792179dc57bc43ab2; affected c827073c95fde388bc65fe5227f944eaf859b9f0; affected 4.17.19 before 4.18
Linux / Linuxaffected 4.18; unaffected 0 before 4.18; unaffected 5.10.265 through 5.10.*; unaffected 5.15.216 through 5.15.*; unaffected 6.1.183 through 6.1.*; unaffected 6.6.148 through 6.6.*; unaffected 6.12.101 through 6.12.*; unaffected 6.18.42 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.