CVE-2023-53782 in Linux
Summary
by MITRE • 12/09/2025
In the Linux kernel, the following vulnerability has been resolved:
dccp: Fix out of bounds access in DCCP error handler
There was a previous attempt to fix an out-of-bounds access in the DCCP error handlers, but that fix assumed that the error handlers only want to access the first 8 bytes of the DCCP header. Actually, they also look at the DCCP sequence number, which is stored beyond 8 bytes, so an explicit pskb_may_pull() is required.
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Analysis
by VulDB Data Team • 03/29/2026
The vulnerability CVE-2023-53782 represents a critical out-of-bounds memory access flaw within the Linux kernel's Datagram Congestion Control Protocol implementation. This issue specifically affects the DCCP error handling mechanisms where the kernel attempts to process incoming packets that trigger error conditions. The vulnerability stems from an insufficient understanding of the DCCP protocol structure and how error handlers interact with packet data. The original fix attempt failed to account for the complete DCCP header layout, creating a security gap that could be exploited by malicious actors.
The technical flaw manifests in the DCCP error handler code where memory access operations extend beyond the intended bounds of the packet data buffer. While the initial patch assumed that error handlers only required access to the first eight bytes of the DCCP header, this assumption proved incorrect as the error handlers also need to examine the DCCP sequence number field which resides beyond the initial eight-byte boundary. The sequence number is a critical component of the DCCP protocol that ensures proper packet ordering and congestion control. When processing malformed or malicious packets, the kernel's error handler attempts to access memory locations that may not be properly mapped or accessible, leading to potential memory corruption or information disclosure.
This vulnerability operates at the kernel level and presents significant operational risks to systems running Linux kernels with DCCP support. The out-of-bounds access could potentially lead to privilege escalation, system crashes, or information leakage that might aid attackers in further compromising the system. The impact is particularly concerning because DCCP is used in real-time applications such as streaming media, VoIP services, and other time-sensitive communications where kernel-level stability is paramount. Attackers could exploit this vulnerability by sending specially crafted DCCP packets that trigger the error handler with malformed data, potentially causing denial of service or unauthorized access to system resources.
The mitigation strategy requires implementing proper bounds checking and explicit memory access validation before any DCCP error handler processes packet data. System administrators should ensure their Linux kernels are updated with the patched version that includes the corrected pskb_may_pull() function call to guarantee sufficient buffer space before accessing the DCCP header fields beyond the initial eight bytes. This fix aligns with common security practices for preventing buffer overflows and out-of-bounds memory access issues. The vulnerability demonstrates the importance of thorough protocol analysis when implementing kernel security fixes, as assumptions about data structure layouts can lead to critical security gaps. Organizations should also consider network-level mitigations such as firewall rules that can filter suspicious DCCP traffic to reduce the attack surface.
This vulnerability maps to CWE-129, which covers improper validation of array indices, and CWE-787, which addresses out-of-bounds write operations. From an ATT&CK perspective, this represents a potential privilege escalation vector through kernel memory corruption, falling under techniques related to kernel exploits and system-level compromise. The issue highlights the complexity of network protocol implementations in kernel space and the necessity for comprehensive testing of edge cases in security-critical code paths. The fix demonstrates the importance of understanding protocol specifications completely rather than making assumptions about data structure layouts, particularly when dealing with network protocols that have complex header formats.