CVE-2026-58185 Overview
CVE-2026-58185 is a use-after-free vulnerability [CWE-416] in the Apache Traffic Server intercept plugin. 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. Remote attackers can trigger the use-after-free over the network without authentication or user interaction. Exploitation impacts availability of the proxy service. The Apache Software Foundation released fixed versions 9.2.15 and 10.1.4 that address the issue.
Critical Impact
Unauthenticated network-based exploitation can disrupt Apache Traffic Server availability by triggering memory corruption within the intercept plugin.
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-2026-58185 published to NVD
- 2026-07-30 - Last updated in NVD database
Technical Details for CVE-2026-58185
Vulnerability Analysis
Apache Traffic Server is a high-performance HTTP proxy and caching server. The intercept plugin allows plugins to take over connection handling from the core proxy. The vulnerability resides in this plugin's lifecycle management of connection or transaction state.
A use-after-free occurs when code continues to reference memory after that memory has been freed. In the intercept plugin, an attacker-triggered sequence of network events causes the plugin to release an object while another code path still holds a reference. Subsequent access to the freed memory produces undefined behavior, typically leading to a process crash and denial of service.
The CVSS 4.0 vector indicates a network-reachable attack surface with no authentication and no user interaction. Only availability of the vulnerable subsystem is impacted according to the published metrics.
Root Cause
The root cause is improper object lifetime management within the Apache Traffic Server intercept plugin [CWE-416]. Reference counting or ownership semantics between the plugin and the transaction state machine do not correctly account for asynchronous release, so a freed object remains reachable through a stale pointer.
Attack Vector
A remote attacker sends crafted HTTP traffic to an Apache Traffic Server instance that uses the intercept plugin. The request pattern drives the plugin into the code path where the freed object is re-referenced, corrupting memory or crashing the worker. No credentials or user interaction are required.
No public proof-of-concept has been released. See the Apache Mailing List Thread for advisory details.
Detection Methods for CVE-2026-58185
Indicators of Compromise
- Unexpected traffic_server process crashes, restarts, or core dumps on hosts running vulnerable versions.
- Segmentation faults or ASAN-style use-after-free traces in Apache Traffic Server diagnostic logs.
- Bursts of anomalous HTTP requests targeting endpoints handled by intercept plugins immediately before a crash.
Detection Strategies
- Inventory all Apache Traffic Server instances and compare versions against 8.1.9, 9.2.14, and 10.1.3 upper bounds to identify vulnerable hosts.
- Correlate proxy worker crash events with upstream and downstream HTTP request logs to identify triggering payloads.
- Enable process crash monitoring on proxy hosts and alert on repeated traffic_server restarts within short windows.
Monitoring Recommendations
- Forward Apache Traffic Server error and diagnostic logs to a centralized analytics platform for retention and correlation.
- Track HTTP 5xx response spikes and connection resets that may indicate exploitation attempts against intercept-plugin endpoints.
- Monitor for reconnaissance patterns from unauthenticated sources scanning proxy infrastructure.
How to Mitigate CVE-2026-58185
Immediate Actions Required
- Upgrade Apache Traffic Server to version 9.2.15 or 10.1.4 on all affected hosts.
- Identify every deployment using intercept plugins and prioritize those instances for patching.
- Restrict network exposure of proxy management and listener interfaces to trusted networks until patching completes.
Patch Information
The Apache Software Foundation fixed the issue in Apache Traffic Server 9.2.15 and 10.1.4. Version 8.x is not listed as receiving a fix; operators still running the 8.x branch should migrate to a supported release. Refer to the Apache Mailing List Thread for the official announcement.
Workarounds
- Disable the intercept plugin if it is not required by the deployment.
- Place a web application firewall or upstream filter in front of Apache Traffic Server to reject malformed requests targeting intercept-handled paths.
- Rate-limit unauthenticated clients to reduce the ability to reliably trigger the freed-memory code path.
# Verify the running Apache Traffic Server version
traffic_server -V
# Example package upgrade on Debian/Ubuntu after adding fixed repository
sudo apt-get update && sudo apt-get install --only-upgrade trafficserver
# Restart the service after upgrade
sudo systemctl restart trafficserver
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
