External risk intelligence

Perl Data::RingBuffer::Shared Stack Buffer Overflow

CVE advisorySeverity: CRITICAL (CVSS 9.8)

CVE-2026-59144

The vulnerability resides in a Perl module for shared memory ring buffers. Exploitation requires a local peer capable of writing to the backing file of the shared memory segment. It is a local, library-level component not designed for direct exposure to the public internet or network-based remote access.

Buffer Overflow

Halo Surface Signal: 1 out of 5 — much less likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This CVE involves a stack buffer overflow vulnerability in a Perl module that handles shared memory ring buffers. The flaw could allow an attacker with local file write access to corrupt memory, potentially leading to broader system compromise. The primary concern is to determine if this specific Perl module is used within our environment and if the conditions for exploitation exist.

Overflow in Perl module could corrupt memory.
Remember if our systems use this Perl module.
Confirm relevance and exposure of this software.

Attack Path

How an attacker could exploit the issue

An attacker with the ability to write to a shared memory buffer's backing file could manipulate the data size used in read operations. This manipulation could lead to a stack buffer overflow when the `ring_read_seq` function copies data, potentially corrupting adjacent memory and enabling the attacker to compromise the system.

Requires ability to write to backing file.
Triggered by reading malformed data.
Leads to stack corruption and potential compromise.

Live Threat

Current exploitation, exposure, and threat context

A stack buffer overflow in Data::RingBuffer::Shared could allow an attacker to overwrite adjacent stack frames. This may occur when a local peer with write access to the backing file manipulates the `elem_size` header value.

Corrupts adjacent stack frames.
Attacker writes a large `elem_size`.
Leads to arbitrary code execution.

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in Data::RingBuffer::Shared impacts applications that use Perl for inter-process communication via shared memory ring buffers. Initial triage involves identifying instances of this module, confirming if the backing files are writable by unauthorized local users, and assessing business criticality. Platform or application owners are responsible for coordinating remediation with vendors if necessary, or implementing compensating controls to mitigate risk until updates can be applied.

Identify application owners and affected systems.
Verify local write access to backing files.
Plan vendor coordination or remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is the Data::RingBuffer::Shared Perl module used for?

This component is a library designed for inter-process communication in Perl applications. It facilitates the exchange of data between different processes by managing shared memory ring buffers, which act as circular queues. Developers use it to move data efficiently across process boundaries on the same system, relying on mapped memory segments to keep information accessible to authorized participants.

What does CWE-121 mean for CVE-2026-59144?

CWE-121 refers to a stack-based buffer overflow. In the context of this CVE, it means the software tries to copy data into a small, fixed-size memory area on the stack without properly checking the length of that data first. Because the library assumes the incoming data is small but actually accepts larger inputs, it overwrites surrounding memory, which can cause the program to crash or behave unexpectedly.

How is this stack buffer overflow triggered?

The flaw is triggered when the library reads from a memory segment that has been modified to contain a misleading size value. An attacker must have the ability to write to the underlying file used for the shared memory buffer. Notably, simply accessing the network or interacting with the application from a remote location does not trigger this; the attacker must be a local peer capable of manipulating the specific shared backing file.

Is my system at risk according to Halo Surface Signal?

According to Halo Surface Signal, risk is considered very unlikely for most environments. The vulnerability is restricted to a library-level component meant for local inter-process communication, not for direct exposure to the public internet. Because exploitation requires local, privileged access to write to a specific backing file, the attack surface is typically confined to local users or processes already authorized to interact with that memory segment.

What should I do if I use Data::RingBuffer::Shared?

First, identify which applications in your environment utilize this Perl module. Once located, verify the security permissions on the backing files associated with the shared memory buffers to ensure they are not writable by unauthorized users. Coordinate with your application owners to plan for updates, as the primary defense is upgrading the module to version 0.04 or later, which includes the necessary validation logic.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.