CVE-2026-59144 EGOR CVE debrief

Who should care

Users of Data::RingBuffer::Shared versions before 0.04 for Perl should be aware of this critical vulnerability. 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. This vulnerability can be exploited by a local peer to gain control over the system.

Technical summary

The vulnerability is caused by the lack of validation of elem_size in ring_read_seq. The function memcpy(out, ring_slot(h, seq), elem_size) uses 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. This can be exploited by a local peer that can write the backing file to leave the header valid while setting a large elem_size. The vulnerability affects Data::RingBuffer::Shared versions before 0.04 for Perl.

Defensive priority

High

Recommended defensive actions

• Update to version 0.04 or later
• Restrict access to the backing file
• Monitor for suspicious activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-21T20:17:03.193Z and has not been modified since then. The NVD entry is currently Deferred. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the vendor. The vulnerability allows a stack buffer overflow via an unvalidated elem_size in ring_read_seq. 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.

Official resources