Summary
CVE-2026-58179 is a high-severity stack-based buffer overflow vulnerability (CWE-121) in the regex_remap plugin of Apache Traffic Server (ATS), caused by insufficient bounds checking on substitution input. The flaw also triggers integer overflows during the same processing path. With a CVSS v3.1 score of 8.1 (High) and full Confidentiality, Integrity, and Availability impact scores (C:H/I:H/A:H), the vulnerability carries significant risk of complete system compromise on affected servers where the plugin is active.
Technical details
- Root cause: The
regex_remapplugin performs URL rewriting by applying user-supplied regex patterns and substitution strings (e.g.,$0–$9,$h,$p,$q). When processing substitution input, the plugin fails to enforce proper bounds, leading to both a stack-based buffer overflow and integer overflows. - Trigger conditions: The vulnerability is reachable over the network without authentication or user interaction; however, it requires that the
regex_remapplugin be loaded and active in the ATS configuration, and that attacker-controllable input reaches the substitution processing logic (AC:H). - Attack vector: Network-accessible; no privileges or user interaction required (AV:N/PR:N/UI:N).
- Impact: CVSS impact metrics of C:H/I:H/A:H indicate potential for full system compromise across confidentiality, integrity, and availability — consistent with the severity of a stack-based buffer overflow in a network-facing plugin.
Affected software
- 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
Severity
- CVSS v3.1: 8.1 (High) —
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS v4.0: 9.2 (Critical) —
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Mitigation and recommended actions
- Immediate: Upgrade Apache Traffic Server to version 9.2.15 or 10.1.4, which contain the official fix from the Apache Software Foundation. Note that the 8.x branch does not have a patched release; organizations running 8.x should migrate to a supported branch (9.2.15 or 10.1.4).
- If immediate patching is not possible: Disable or remove the
regex_remapplugin from the ATS configuration to eliminate the vulnerable code path. Restrict network access to ATS instances to trusted clients where feasible.
IONIX Status
The IONIX research team is tracking ongoing exploitation attempts and recommends immediate patching. Potentially affected assets are outlined in this post.

