CVE-2023-53839 dccp: fix data-race around dp->dccps_mss_cache
A data race in the Linux kernel DCCP protocol allows attackers to cause a denial of service by triggering inconsistent MSS cache reads.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53839?
CVE-2023-53839 is a vulnerability in Linux, published on 9 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
dccp: fix data-race around dp->dccps_mss_cache
dccp_sendmsg() reads dp->dccps_mss_cache before locking the socket. Same thing in do_dccp_getsockopt().
Add READ_ONCE()/WRITE_ONCE() annotations, and change dccp_sendmsg() to check again dccps_mss_cache after socket is locked.
Which versions are affected by CVE-2023-53839?
How do I fix CVE-2023-53839?
Apply the vendor's patch.
Is CVE-2023-53839 being exploited?
There is no known exploitation of CVE-2023-53839 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53839, DEBIAN-CVE-2023-53839, GHSA-8252-q96p-5jpg, UBUNTU-CVE-2023-53839.