CVE-2026-49975: Apache HTTP Server: mod_http2 denial of service

highCVSS 7.5CVE-2026-49975

CSIRTS triage

vendor: Apache product: Apache HTTP Server Denial of service

What: A denial of service vulnerability exists in mod_http2.
Who is affected: Deployments of Apache HTTP Server using mod_http2.
Urgency: Remediation is high urgency due to the high severity of the denial of service risk.
Action: Update to the latest version of Apache HTTP Server.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch Apache HTTP Server

Get an email when a new Apache HTTP Server advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.5
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-49975

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Elevated exploitation riskCVE-2026-4997511.5% 30-day exploitation probability — well above the norm. Schedule remediation this cycle. Riskier than 96% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-49975	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

high[UPDATE] [high] Apache HTTP Server: Multiple vulnerabilitiescert-bund
high[UPDATE] [high] HTTP/2 implementations: Vulnerability allows denial of servicecert-bund
unknownZimbra Denial of Service Vulnerabilityhkcert

Recent advisories for Apache HTTP Server

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

high[UPDATE] [high] Apache HTTP Server: Multiple vulnerabilitiescert-bund · 2026-07-09
high[UPDATE] [high] Apache HTTP Server: Multiple vulnerabilitiescert-bund · 2026-07-09
high[UPDATE] [high] Apache HTTP Server: Multiple vulnerabilitiescert-bund · 2026-07-09
unknownUSN-8516-1: Apache HTTP Server vulnerabilitiesubuntu · 2026-07-08
mediumCVE-2026-56139: Generation of Error Message Containing Sensitive Information vulnerability in Apache Camel Und…nvd · 2026-07-06
mediumCVE-2026-49365: Generation of Error Message Containing Sensitive Information vulnerability in Apache Camel Net…nvd · 2026-07-06