CVE-2023-53839 in Linux
Summary
by MITRE • 12/09/2025
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.
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Analysis
by VulDB Data Team • 03/30/2026
The vulnerability identified as CVE-2023-53839 represents a critical data race condition within the Linux kernel's Datagram Congestion Control Protocol implementation. This issue affects the dccp subsystem where concurrent access to the dccps_mss_cache field creates potential for inconsistent data states during socket operations. The flaw manifests when dccp_sendmsg() and do_dccp_getsockopt() functions access the dp->dccps_mss_cache field without proper synchronization mechanisms, creating a window where multiple threads or processes can simultaneously read and modify this shared resource. Such race conditions are particularly dangerous in kernel space as they can lead to memory corruption, system instability, and potentially arbitrary code execution.
The technical root cause of this vulnerability stems from improper memory access synchronization within the DCCP protocol implementation. When dccp_sendmsg() attempts to read the dccps_mss_cache field before acquiring the socket lock, it creates a scenario where the value being read may be stale or inconsistent with the actual state of the socket. Similarly, do_dccp_getsockopt() exhibits the same problematic behavior by accessing the cache field without appropriate locking mechanisms. This pattern violates fundamental concurrency control principles and creates a classic data race condition where multiple execution paths access shared memory without proper mutual exclusion. The vulnerability aligns with CWE-362, which specifically addresses Race Conditions, and represents a failure to implement proper atomic operations or memory barriers.
The operational impact of CVE-2023-53839 extends beyond simple performance degradation to potentially compromising system integrity and availability. An attacker could exploit this vulnerability to cause unpredictable behavior in DCCP-based applications, leading to service disruption, data corruption, or system crashes. The vulnerability affects systems running Linux kernels that implement the DCCP protocol, particularly those handling high-concurrency network traffic. Given that DCCP is used in various real-time applications including streaming media, VoIP services, and other time-sensitive communications, the exploitation of this race condition could result in significant service interruptions. The vulnerability also poses risks to network infrastructure components that rely on DCCP for efficient data transmission, potentially enabling denial-of-service attacks or data manipulation scenarios.
The mitigation strategy for CVE-2023-53839 involves implementing proper memory access annotations and synchronization mechanisms. The fix requires adding READ_ONCE() and WRITE_ONCE() annotations to ensure proper memory ordering and prevent compiler optimizations from reordering memory accesses. Additionally, the dccp_sendmsg() function must be modified to perform a second check of dccps_mss_cache after acquiring the socket lock, ensuring that the value read is consistent with the locked state of the socket. This approach addresses the fundamental concurrency issue by ensuring that all accesses to the shared cache field occur within proper synchronization boundaries. The solution aligns with ATT&CK technique T1070.006, which involves the use of system binary proxies, and represents a defensive programming approach that prevents race conditions through proper memory access control. System administrators should apply the kernel patch immediately to prevent exploitation, as this vulnerability can be leveraged by malicious actors to gain unauthorized access to network services or disrupt critical communications infrastructure.