CVE-2024-38479: Apache Traffic Server Input Vulnerability

CVE-2024-38479 Overview

CVE-2024-38479 is an improper input validation vulnerability [CWE-20] in Apache Traffic Server, the open-source HTTP/HTTPS caching proxy used to scale web content delivery. The flaw affects versions 8.0.0 through 8.1.11 and 9.0.0 through 9.2.5. An unauthenticated remote attacker can exploit the issue over the network without user interaction. The Apache Software Foundation recommends upgrading to 9.2.6 or 10.0.2, which remediate the issue.

Critical Impact
Remote attackers can send malformed input to Apache Traffic Server instances and compromise the integrity of proxied traffic without authentication.

Affected Products

Apache Traffic Server 8.0.0 through 8.1.11
Apache Traffic Server 9.0.0 through 9.2.5
Downstream distributions including Debian LTS packages of trafficserver

Discovery Timeline

2024-11-14 - CVE-2024-38479 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-38479

Vulnerability Analysis

The vulnerability resides in how Apache Traffic Server validates input received over the network. Improper input validation [CWE-20] occurs when the proxy accepts or processes data without enforcing the expected syntactic or semantic constraints. Because Apache Traffic Server sits between clients and origin servers, malformed input that bypasses validation can alter how requests or responses are processed downstream.

The issue impacts integrity rather than confidentiality or availability. Exploitation requires no privileges and no user interaction, and the attack surface is reachable across the network on any port the proxy serves. See the Apache Thread Discussion for the upstream notice.

Root Cause

The defect stems from missing or insufficient validation of attacker-controlled input fields processed by the proxy. When validation routines fail to reject malformed values, the server treats them as legitimate and forwards them through its caching and routing logic. Apache resolved the defect in 9.2.6 and confirmed 10.0.2 is not affected.

Attack Vector

An unauthenticated attacker delivers crafted requests directly to an exposed Apache Traffic Server instance. Because the proxy is typically deployed at the network edge, exploitation does not require pivoting through internal systems. The attack does not crash the service, which makes detection harder without protocol-aware monitoring.

No public proof-of-concept code is currently available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2024-38479

Indicators of Compromise

Unexpected or malformed HTTP requests in Apache Traffic Server access logs containing unusual header values or non-standard request structures.
Cache entries or proxied responses that do not match the expected origin response patterns.
Anomalous traffic spikes targeting Apache Traffic Server listening ports from unfamiliar source addresses.

Detection Strategies

Inventory all Apache Traffic Server deployments and compare versions against the affected ranges 8.0.0–8.1.11 and 9.0.0–9.2.5.
Enable verbose request logging in records.config and review for malformed inputs that previous filters would have rejected.
Correlate proxy logs with upstream origin server logs to surface inconsistencies introduced between client request and origin delivery.

Monitoring Recommendations

Forward Apache Traffic Server logs to a centralized analytics platform and alert on parsing errors or protocol anomalies.
Monitor for new CVE references against the apache:traffic_server component in vulnerability management tooling.
Track outbound requests from the proxy tier for deviations that could indicate tampered or smuggled requests.

How to Mitigate CVE-2024-38479

Immediate Actions Required

Upgrade Apache Traffic Server to version 9.2.6 or 10.0.2 as recommended by the Apache Software Foundation.
Apply distribution-specific patches such as the Debian LTS update referenced in the Debian LTS Security Announcement.
Restrict network exposure of Apache Traffic Server administrative interfaces to trusted management networks only.

Patch Information

The Apache Software Foundation released fixed versions 9.2.6 and 10.0.2. Operators on the 8.x branch must migrate to a supported branch because no patched 8.x release is listed in the advisory. Refer to the Apache Thread Discussion for the upstream announcement.

Workarounds

Place a hardened upstream reverse proxy or web application firewall in front of Apache Traffic Server to filter malformed input.
Disable any non-essential request processing features or plugins that increase exposure to untrusted input.
Limit accepted HTTP methods and enforce strict request size and header limits at the network edge until patching is complete.

bash

# Verify the installed Apache Traffic Server version and upgrade if affected
traffic_server -V

# Example Debian/Ubuntu upgrade workflow
sudo apt update
sudo apt install --only-upgrade trafficserver
sudo systemctl restart trafficserver