CVE-2026-59144 in Data::RingBuffer::Shared
Summary
by MITRE • 07/21/2026
Data::RingBuffer::Shared versions before 0.04 for Perl allow a stack buffer overflow via an unvalidated elem_size in ring_read_seq.
The attach-time validator ring_validate_header checks the capacity-overflow and total_size consistency of the header but never caps elem_size against the destination size. ring_read_seq does memcpy(out, ring_slot(h, seq), elem_size) with elem_size read raw from the mmap'd segment, copying into a fixed 8-byte destination scalar. An elem_size larger than 8 bytes writes past the destination.
A local peer that can write the backing file can leave the header valid while setting a large elem_size, so the next read copies a file-controlled length into the fixed 8-byte stack buffer, corrupting adjacent stack frames.
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Analysis
by VulDB Data Team • 07/21/2026
The vulnerability exists in Data::RingBuffer::Shared Perl module versions prior to 004, specifically within the ring_read_seq function that processes data from shared memory segments. This represents a classic stack buffer overflow condition where the element size parameter is not properly validated against the destination buffer boundaries. The module's design includes an attach-time validation mechanism called ring_validate_header which performs checks on capacity-overflow and total_size consistency but fails to impose any bounds on the elem_size field against the actual destination buffer size. This validation gap creates a critical security flaw that allows malicious actors to manipulate the shared memory segment header.
The technical flaw manifests when ring_read_seq executes memcpy(out, ring_slot(h, seq), elem_size) where elem_size is directly read from the memory-mapped segment without proper bounds checking. The destination buffer for this operation is fixed at 8 bytes, representing a scalar value in the stack frame. When an attacker can control the backing file and set an elem_size value exceeding 8 bytes, the memcpy operation overflows the intended destination, writing beyond the allocated stack space and potentially corrupting adjacent stack frames. This vulnerability is particularly dangerous because it operates within the context of shared memory segments where local peers with write access to the backing file can manipulate the header structure without triggering the existing validation checks.
The operational impact of this vulnerability extends beyond simple data corruption, as it provides a potential pathway for privilege escalation and arbitrary code execution in scenarios where the vulnerable application runs with elevated privileges. The stack buffer overflow allows attackers to overwrite return addresses, function pointers, and other critical stack metadata, potentially enabling code injection attacks. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow and can be mapped to ATT&CK technique T1059.007 for execution through Perl scripts. The attack vector requires local access to write the backing file but does not require network connectivity or complex exploitation chains.
Mitigation strategies should focus on implementing proper bounds checking for elem_size parameters against destination buffer sizes in all memory copy operations. The module should be updated to enforce maximum element size limits that prevent overflow conditions, and validation routines must be enhanced to check elem_size values against the actual buffer capacity. Additionally, input sanitization should be implemented at the point of data extraction from shared memory segments to ensure that all parameters are properly validated before use. System administrators should also consider implementing memory protection mechanisms such as stack canaries and address space layout randomization to reduce the effectiveness of potential exploitation attempts. The vulnerability highlights the importance of comprehensive validation in shared memory operations and demonstrates how seemingly minor oversights in input sanitization can lead to critical security flaws.