CVE-2026-58180: Apache Traffic Server Buffer Overflow

CVE-2026-58180 Overview

CVE-2026-58180 is a stack-based buffer overflow [CWE-121] in the txn_box plugin for Apache Traffic Server. The plugin overflows the stack when processing attacker-controlled input received over the network. The flaw affects Apache Traffic Server versions 8.0.0 through 8.1.9, 9.0.0 through 9.2.14, and 10.0.0 through 10.1.3. The Apache Software Foundation released fixed versions 9.2.15 and 10.1.4 to remediate the issue. Because Apache Traffic Server operates as a reverse proxy and HTTP cache, exploitable instances typically face the public internet, exposing them to remote unauthenticated attacks that can crash the proxy process.

Critical Impact
Remote unauthenticated attackers can trigger a stack overflow in the txn_box plugin, corrupting the process stack and causing denial of service or potential code execution on Apache Traffic Server proxy instances.

Affected Products

Apache Traffic Server 8.0.0 through 8.1.9
Apache Traffic Server 9.0.0 through 9.2.14
Apache Traffic Server 10.0.0 through 10.1.3

Discovery Timeline

2026-07-29 - CVE-2026-58180 published to NVD
2026-07-30 - Last updated in NVD database

Technical Details for CVE-2026-58180

Vulnerability Analysis

Apache Traffic Server is a high-performance reverse proxy and forward proxy. The txn_box plugin extends the proxy with transaction manipulation logic, letting operators inspect and modify HTTP requests, responses, and headers using declarative rules. The plugin processes attacker-influenced request data during transaction handling.

The vulnerability is classified as a stack-based buffer overflow [CWE-121]. Attacker-controlled input reaches a fixed-size stack buffer inside the txn_box plugin without adequate bounds enforcement. When the input exceeds the buffer capacity, the overflow overwrites adjacent stack memory, including saved registers and return addresses.

The network attack vector allows exploitation without authentication. Any client capable of sending crafted HTTP traffic to an affected proxy can trigger the condition. Successful exploitation most commonly results in the traffic_server process crashing, interrupting proxy availability for downstream applications.

Root Cause

The root cause is missing or insufficient input length validation in the txn_box plugin before copying attacker-controlled data into a stack-allocated buffer. Stack buffers have compile-time bounds, and copying data beyond those bounds corrupts the call frame. Modern mitigations such as stack canaries usually convert this class of bug into a process abort rather than reliable code execution, though outcomes depend on the compiler options used to build the deployed binary.

Attack Vector

Exploitation requires network reachability to an Apache Traffic Server instance running a vulnerable txn_box build. The attacker sends an HTTP request whose fields are shaped to reach the vulnerable code path in the plugin and exceed the internal stack buffer size. No credentials or user interaction are required.

A proof-of-concept is not publicly available at time of writing. Technical details are documented in the Apache Mailing List Thread.

Detection Methods for CVE-2026-58180

Indicators of Compromise

Unexpected crashes or restarts of the traffic_server process, particularly with signals indicating stack corruption such as SIGSEGV or SIGABRT.
Core dumps referencing symbols inside the txn_box plugin shared object.
Bursts of malformed or oversized HTTP request headers preceding proxy instability.
Gaps in proxy access logs coinciding with restart events managed by traffic_manager.

Detection Strategies

Inventory Apache Traffic Server deployments and confirm plugin configuration in plugin.config for txn_box.so.
Compare installed versions against the fixed releases 9.2.15 and 10.1.4 to identify exposure.
Alert on repeated traffic_server process exits in service manager logs (systemd, supervisord).

Monitoring Recommendations

Forward traffic.out, diags.log, and system journal entries to a centralized logging platform for correlation.
Monitor for HTTP requests containing abnormally long headers or fields targeting endpoints handled by txn_box rules.
Track process uptime metrics for the proxy tier and alert on unexpected restarts.

How to Mitigate CVE-2026-58180

Immediate Actions Required

Upgrade Apache Traffic Server to version 9.2.15 or 10.1.4, which contain the fix for CVE-2026-58180.
If immediate patching is not possible, disable the txn_box plugin by removing its entry from plugin.config and reloading the proxy.
Restrict network exposure of affected instances to trusted upstream load balancers or WAFs until patched.

Patch Information

The Apache Software Foundation fixed the vulnerability in Apache Traffic Server 9.2.15 and 10.1.4. Users on the 8.x branch should upgrade to a supported release, as fixes are provided for the 9.x and 10.x branches. Refer to the Apache Mailing List Thread for the official announcement.

Workarounds

Remove or comment out the txn_box.so entry in plugin.config and restart the proxy to eliminate the vulnerable code path.
Place a filtering layer such as a WAF in front of the proxy to drop requests with oversized headers or fields.
Enable operating system hardening such as ASLR and stack protector features to reduce the reliability of exploitation while patches are staged.

bash

# Verify the running Apache Traffic Server version
traffic_server -V

# Temporary workaround: disable the txn_box plugin
sudo sed -i 's|^txn_box.so|# txn_box.so|' /etc/trafficserver/plugin.config
sudo traffic_ctl server restart

# Confirm the plugin is no longer loaded
traffic_ctl plugin msg txn_box status || echo "txn_box not loaded"