CVE-2026-68335
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).
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.14% probability · 3th percentile
- CISA KEV
- Not listed
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/03c574112e5d066df0ddce36d7438e850bcf3050
- https://git.kernel.org/stable/c/0f8690e3869109cd5803ccb400889d20a0b54e0e
- https://git.kernel.org/stable/c/1e2e2d9806944fe485824d617c8b7c78116c22db
- https://git.kernel.org/stable/c/5521ae71e32a8069ed4ca6e792179dc57bc43ab2
- https://git.kernel.org/stable/c/742ff6f02545212e991cd8b45011e40d2c2ef25a
- https://git.kernel.org/stable/c/9591042533140dfe6608d9344806d567dcd39d02
- https://git.kernel.org/stable/c/abff41fd928328bbf3dda1140beb2e61fa424ccd
- https://git.kernel.org/stable/c/cfb3ce07b705e486e022a2f2b1242b48f13981ff
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.