External risk intelligence

Apache Traffic Server Regex Remap Plugin Stack and Integer Overflow

CVE advisorySeverity: CRITICAL (CVSS 9.2)

CVE-2026-58179

Apache Traffic Server is a high-performance HTTP proxy and caching server designed specifically to function as an internet-facing edge service or gateway. Its core deployment pattern involves handling public web traffic directly at the network perimeter.

Apache Traffic Server

8.0.0 to 8.1.99.0.0 to before 9.2.1510.0.0 to before 10.1.4

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A vulnerability in the Apache Traffic Server regex_remap plugin could allow an attacker to cause a stack and integer overflow when processing substitution input. This impacts specific versions of Apache Traffic Server, a critical component often used as an internet-facing gateway. Understanding the relevance and exposure of this plugin is the primary concern.

Plugin overflow can crash the server.
Edge service vulnerability requires executive awareness.
Confirm if this critical plugin is in use.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by sending specially crafted requests to a network-exposed Apache Traffic Server instance. This would trigger a buffer overflow within the regex_remap plugin, potentially leading to a denial-of-service condition or unauthorized code execution.

Network access required.
Triggered by crafted substitution input.
Leads to denial-of-service or code execution.

Live Threat

Current exploitation, exposure, and threat context

The Apache Traffic Server regex_remap plugin can be exploited through stack and integer overflows when processing substitution input. This could allow an attacker to impact the availability and integrity of the server when handling specific HTTP requests.

Server availability and integrity.
Malformed substitution input in requests.
Denial of service or code execution.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and infrastructure teams are likely responsible for addressing this vulnerability in Apache Traffic Server, as it is an internet-facing edge service. The first practical step is to identify all instances of the affected technology, assess their exposure and business criticality, confirm ownership, and then plan remediation within a maintenance window.

Identify affected Apache Traffic Server instances.
Verify reachability and business criticality.
Plan risk-based remediation and upgrades.

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 Apache Traffic Server and how is it used?

Apache Traffic Server is a high-performance HTTP proxy and caching server. It acts as an intermediary for web traffic, typically deployed at the edge of a network to handle requests between clients and back-end servers, improve performance through content caching, and serve as a secure gateway for web applications.

What does the CVE-2026-58179 vulnerability mean?

This vulnerability is classified as a stack and integer overflow (CWE-121). It occurs in the regex_remap plugin, which is a tool used for URL rewriting. The flaw allows memory management errors when the plugin processes specially crafted input, which can result in the server crashing or potentially allowing unauthorized code execution.

How is the regex_remap plugin triggered?

The vulnerability is triggered when the affected server processes malformed or specifically crafted substitution input through the regex_remap plugin. It is important to note that standard, well-formed traffic that does not utilize the specific remapping features susceptible to this memory handling error will not trigger the bug.

Is my Apache Traffic Server instance at risk?

According to Halo Surface Signal, Apache Traffic Server is frequently deployed as an internet-facing edge service. Because the vulnerability requires network access to the server, any instance exposed to the public internet should be considered at higher risk compared to those strictly isolated within an internal network.

What should I do to address CVE-2026-58179?

The primary step is to identify all running instances of Apache Traffic Server to determine if the vulnerable regex_remap plugin is in use. Once identified, you should plan to upgrade your software to version 9.2.15 or 10.1.4, as these releases contain the necessary fixes to resolve the memory overflow issues.

References

lists.apache.org/thread/5prl9glcm9g2swnq9hqxvnokylm1gr6d

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.