# CVE-2026-49975 — Apache HTTP Server

> As of 2026-08-19, CVE-2026-49975 is a HIGH-severity vulnerability in Apache HTTP Server, CVSS v3.1 7.5, EPSS 4.1% (90.6th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-49975, most recently “HTTP/2 Bomb — Remote DoS via HPACK Indexed-Reference Compression Bomb + Zero-Window Flow-Control Hold Affecting nginx, Apache httpd, IIS, Envoy & Cloudflare Pingora (CVE-2026-49975, Public PoC)”.

**Last updated:** 2026-08-19

## What is CVE-2026-49975?

Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests. This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.

The record classifies CVE-2026-49975 under weakness classes [CWE-789](https://cwe.mitre.org/data/definitions/789.html), [CWE-409](https://cwe.mitre.org/data/definitions/409.html). 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 availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 141 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.5 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **EPSS (FIRST):** 4.1% probability of exploitation in the next 30 days, higher than 90.6% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 9.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-08, last modified 2026-08-19

## Is CVE-2026-49975 being exploited?

Weaponised exploit code for CVE-2026-49975 is publicly available. 11 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 36 in the Threadlinqs vulnerability feed.

- [mrx-arafat/CVE-2026-49975-POC](https://github.com/mrx-arafat/CVE-2026-49975-POC) (github)
- [EQSTLab/CVE-2026-49975](https://github.com/EQSTLab/CVE-2026-49975) (github)
- [fevar54/Proof-of-Concept-POC---CVE-2026-49975-HTTP-2-Bomb-](https://github.com/fevar54/Proof-of-Concept-POC---CVE-2026-49975-HTTP-2-Bomb-) (github)
- [LSG-PolarBear/CVE-2026-49975](https://github.com/LSG-PolarBear/CVE-2026-49975) (github)
- [obrige/http2-bomb](https://github.com/obrige/http2-bomb) (github)
- [LiaoZiqi-GZFLS/CVE-2026-49975](https://github.com/LiaoZiqi-GZFLS/CVE-2026-49975) (github)
- [naheeju/POC-CVE-2026-49975](https://github.com/naheeju/POC-CVE-2026-49975) (github)
- [renzi25031469/CVE-2026-49975-HTTP-2-Bomb](https://github.com/renzi25031469/CVE-2026-49975-HTTP-2-Bomb) (github)

## Affected products and versions

- [Apache Software Foundation](https://intel.threadlinqs.com/vendors/apache-software-foundation): Apache HTTP Server

## How to fix CVE-2026-49975

No vendor patch reference has been recorded for CVE-2026-49975 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-2026-49975

1 tracked threat in the Threadlinqs corpus references CVE-2026-49975, either in the campaign’s CVE list or as an indicator on the campaign record.

- [HTTP/2 Bomb — Remote DoS via HPACK Indexed-Reference Compression Bomb + Zero-Window Flow-Control Hold Affecting nginx, Apache httpd, IIS, Envoy & Cloudflare Pingora (CVE-2026-49975, Public PoC)](https://intel.threadlinqs.com/threat/TL-2026-0668) — HIGH · 2026-06-03

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [httpd.apache.org — vendor advisory](https://httpd.apache.org/security/vulnerabilities_24.html)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-49975
Full detection coverage and IOCs for threats exploiting CVE-2026-49975 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp