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CVE-2026-68335

rds: drop incoming messages that cross network namespace boundaries

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.18, 5.10.265, 5.15.216, 6.1.183, 6.6.148, and 3 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 742ff6f02545212e991cd8b45011e40d2c2ef25a; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in abff41fd928328bbf3dda1140beb2e61fa424ccd; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 03c574112e5d066df0ddce36d7438e850bcf3050; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 1e2e2d9806944fe485824d617c8b7c78116c22db; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in cfb3ce07b705e486e022a2f2b1242b48f13981ff; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 9591042533140dfe6608d9344806d567dcd39d02; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 0f8690e3869109cd5803ccb400889d20a0b54e0e; From c809195f5523dd4d09403bbb1c9732d548aa0d1e · fixed in 5521ae71e32a8069ed4ca6e792179dc57bc43ab2; From 4.17.19 · fixed in 4.18

  • Linux Linux

    4.18

  • KernelLinux

    From 4.18.0 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.148; From 6.7.0 · fixed in 6.12.101; From 6.13.0 · fixed in 6.18.42; From 6.19.0 · fixed in 7.1.6

References 8

git.kernel.org