CVE-2023-53825

What it is

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.

At a glance

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2025-12-09 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:46 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: not scored yet.
• Fix: none linked yet, which raises it.

Details

Published

2025-12-09 16:17 UTC

Last modified

2026-06-17 06:46 UTC

Exploit probability

0.3% · EPSS, next 30 days

Record status

Deferred

Is it in your code?

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