What is CVE-2026-56154?
Use After Free vulnerability in Apache HTTP Server's mod_rewrite when using lookahead (%{LA-U:HTTP:...}) This issue affects Apache HTTP Server: from 2.4.0 through 2.4.68.
The record classifies CVE-2026-56154 under weakness class CWE-416. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 22 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 0.5% probability of exploitation in the next 30 days, higher than 45.0% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6.7/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-10-01
Is CVE-2026-56154 being exploited?
It currently carries a trending score of 44 in the Threadlinqs vulnerability feed.
Affected products and versions
- Apache Software Foundation: Apache HTTP Server
How to fix CVE-2026-56154
No vendor patch reference has been recorded for CVE-2026-56154 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-56154
1 tracked threat in the Threadlinqs corpus references CVE-2026-56154, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on .