CVE-2023-53825

kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg().

State: Published
Severity: Not scored
Published: Dec 9, 2025
Updated: May 11, 2026
Reserved: Dec 9, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

kcm: Fix error handling for SOCK_DGRAM in kcm_sendmsg().

syzkaller found a memory leak in kcm_sendmsg(), and commit c821a88bd720 ("kcm: Fix memory leak in error path of kcm_sendmsg()") suppressed it by updating kcm_tx_msg(head)->last_skb if partial data is copied so that the following sendmsg() will resume from the skb.

However, we cannot know how many bytes were copied when we get the error. Thus, we could mess up the MSG_MORE queue.

When kcm_sendmsg() fails for SOCK_DGRAM, we should purge the queue as we do so for UDP by udp_flush_pending_frames().

Even without this change, when the error occurred, the following sendmsg() resumed from a wrong skb and the queue was messed up. However, we have yet to get such a report, and only syzkaller stumbled on it. So, this can be changed safely.

Note this does not change SOCK_SEQPACKET behaviour.

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 21b467735b0888a8daa048f83d3b9b50fdab71ceAffected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before d4b8f380b0a041ee6a84fdac14127d8fe1dcad7bAffected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 1ce8362b4ac6b8e65fd04a22ea37ec776ee1ec5bAffected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 2e18493c421428a936946c452461b8e979088f17Affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 55d2e7c1ab8eaa7b62575b8a4194132795d1f9fcAffected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before e5b28ce127a690f3acc49a6a342e6c9442c9edd6Affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 992b2ac783aad360b98ed9d4686e86176a20f6f1Affected ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before a22730b1b4bf437c6bbfdeff5feddf54be4aeadaAffected
LinuxLinux	4.6Affected before 4.6Not affected 4.14.326 through 4.14.Not affected 4.19.295 through 4.19.Not affected 5.4.257 through 5.4.Not affected 5.10.195 through 5.10.Not affected 5.15.132 through 5.15.Not affected 6.1.54 through 6.1.Not affected 6.5.4 through 6.5.*Not affected 6.6 and laterNot affected

Product

Versions

LinuxLinux

ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 21b467735b0888a8daa048f83d3b9b50fdab71ceAffected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before d4b8f380b0a041ee6a84fdac14127d8fe1dcad7bAffected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 1ce8362b4ac6b8e65fd04a22ea37ec776ee1ec5bAffected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 2e18493c421428a936946c452461b8e979088f17Affected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 55d2e7c1ab8eaa7b62575b8a4194132795d1f9fcAffected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before e5b28ce127a690f3acc49a6a342e6c9442c9edd6Affected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before 992b2ac783aad360b98ed9d4686e86176a20f6f1Affected
ab7ac4eb9832e32a09f4e8042705484d2fb0aad3 to before a22730b1b4bf437c6bbfdeff5feddf54be4aeadaAffected

LinuxLinux

4.6Affected
before 4.6Not affected
4.14.326 through 4.14.*Not affected
4.19.295 through 4.19.*Not affected
5.4.257 through 5.4.*Not affected
5.10.195 through 5.10.*Not affected
5.15.132 through 5.15.*Not affected
6.1.54 through 6.1.*Not affected
6.5.4 through 6.5.*Not affected
6.6 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.