CVE-2026-22068: Apache Traffic Server Regex Vulnerability

CVE-2026-22068 Overview

CVE-2026-22068 is a Regular Expression without Anchors vulnerability [CWE-777] in Apache Traffic Server (ATS). The flaw affects ATS versions 10.0.X through 10.1.3 and 9.0.X through 9.2.14. The Apache Software Foundation released fixed versions 9.2.15 and 10.1.4 to address the issue.

The vulnerability stems from regular expressions used without anchoring metacharacters. Attackers can craft input that matches unintended portions of a string, bypassing the intended security boundary enforced by the regex. The issue is exploitable over the network without authentication or user interaction.

Critical Impact
Attackers can bypass access controls or routing policies enforced by unanchored regular expressions in Apache Traffic Server, affecting downstream systems that trust the proxy's filtering decisions.

Affected Products

Apache Traffic Server 9.0.X through 9.2.14
Apache Traffic Server 10.0.X through 10.1.3
Fixed in Apache Traffic Server 9.2.15 and 10.1.4

Discovery Timeline

2026-07-29 - CVE-2026-22068 published to NVD
2026-07-30 - Last updated in NVD database

Technical Details for CVE-2026-22068

Vulnerability Analysis

CVE-2026-22068 is classified under [CWE-777: Regular Expression without Anchors]. Regex anchors such as ^ and $ constrain a pattern to match the beginning or end of a string. When these anchors are omitted, the regex matches any substring, including untrusted portions injected by an attacker.

In a reverse proxy such as Apache Traffic Server, unanchored regular expressions are commonly used in ACL rules, remap configurations, and header validation. An attacker can supply a request whose URI, host, or header contains a substring that satisfies the pattern while smuggling additional content past the intended check.

The scope-changed impact indicates the confidentiality of subsequent systems can be compromised even though ATS itself does not lose data integrity or availability.

Root Cause

The root cause lies in regex patterns compiled without start-of-string (^) and end-of-string ($) anchors within Apache Traffic Server's rule evaluation logic. Any input containing a matching substring passes validation, allowing crafted values to be accepted where a full-string match was expected.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker sends a specially crafted HTTP request to the proxy. The request contains a URI, hostname, or header that embeds a benign-looking substring matching the unanchored pattern, while the surrounding content routes traffic or grants access that should have been denied. See the Apache Security Mailing List Thread for advisory details.

Detection Methods for CVE-2026-22068

Indicators of Compromise

HTTP requests to Apache Traffic Server containing unusual URI patterns that combine trusted substrings with attacker-controlled suffixes or prefixes.
Access log entries showing requests routed to internal upstreams that should have been blocked by ACL rules.
Anomalous host header values or path segments where a legitimate value appears embedded within a longer string.

Detection Strategies

Audit all remap.config, ip_allow.config, and plugin regex rules for patterns missing ^ and $ anchors.
Review proxy access logs for requests whose matched routing rule appears inconsistent with the effective destination.
Correlate ATS access logs with upstream application logs to identify requests reaching origins that should have been filtered.

Monitoring Recommendations

Ingest Apache Traffic Server access and error logs into a centralized logging platform for continuous review.
Alert on spikes in requests matching ACL rules that were rarely triggered historically.
Track version banners of ATS instances across the environment to confirm patched builds are deployed.

How to Mitigate CVE-2026-22068

Immediate Actions Required

Upgrade Apache Traffic Server to version 9.2.15 or 10.1.4 as recommended by the Apache Software Foundation.
Inventory all ATS instances across production, staging, and edge locations to confirm affected versions.
Review custom regex rules in ATS configuration files and add anchors where full-string matching is intended.

Patch Information

The Apache Software Foundation released Apache Traffic Server 9.2.15 and 10.1.4 to fix CVE-2026-22068. Users on any 10.0.X through 10.1.3 release must upgrade to 10.1.4. Users on any 9.0.X through 9.2.14 release must upgrade to 9.2.15. Refer to the Apache Security Mailing List Thread for the official advisory.

Workarounds

Rewrite regex patterns in ATS configuration to include explicit ^ and $ anchors before upgrading, where operationally feasible.
Add upstream Web Application Firewall (WAF) rules that enforce strict validation of URI, host, and header fields.
Restrict administrative access to ATS configuration files to limit unauthorized rule changes during the remediation window.

bash

# Verify installed Apache Traffic Server version
traffic_server -V

# Example of anchoring a regex in remap.config
# Vulnerable pattern (unanchored):
# map_with_recv_port /api/v1/.* http://backend.internal/
# Hardened pattern (anchored):
# map_with_recv_port ^/api/v1/[a-zA-Z0-9_/-]+$ http://backend.internal/