[NEW] [medium] HTTP/2 Server: Vulnerability allows Denial of Service

mediumCVE-2026-59173

A remote, anonymous attacker can exploit a vulnerability in various HTTP/2 server implementations such as the Apache Traffic Server to conduct a Denial of Service attack.

CSIRTS triage

vendor: Apache product: Traffic Server Denial of service

What: A vulnerability in HTTP/2 server implementations can lead to Denial of Service attacks.
Who is affected: Users of various HTTP/2 server implementations are affected.
Urgency: Remediation is necessary to prevent potential Denial of Service attacks.
Action: Apply patches or mitigations for the affected HTTP/2 server implementations.

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

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Details

Source: CERT-Bund (BSI) Security Advisories (DE · national-cert · site)
Severity: medium
Published: 2026-07-20
Exploitation: Not in CISA KEV at last sync
Language: Machine-translated to English — verify against the original

Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2026-2388

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.

Low exploitation riskCVE-2026-591730.51% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 40% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-59173	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

highCVE-2026-59173: Uncontrolled Resource Consumption vulnerability in Apache Traffic Server. This issue affects A…nvd

Recent advisories for HTTP/2 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.

mediumCVE-2026-65100: Apache Traffic Server updates the HTTP/2 HPACK dynamic table before confirming the header bloc…nvd · 2026-07-29
mediumCVE-2026-65325: Apache Traffic Server reuses multiplexed HTTP/2 origin connections without verifying the serve…nvd · 2026-07-29
highCVE-2026-65324: Apache Traffic Server drops the per-stream buffer cap when dechunking HTTP/2 or HTTP/3 respons…nvd · 2026-07-29
highCVE-2026-58153: Apache Traffic Server forwards HTTP/2 origin trailers to HTTP/1 clients without proper chunked…nvd · 2026-07-29
highCVE-2026-58151: Apache Traffic Server can be crashed or driven to resource exhaustion by abusive HTTP/2 framin…nvd · 2026-07-29
criticalCVE-2026-58150: Apache Traffic Server does not reject Transfer-Encoding in HTTP/2 requests, allowing downgrade…nvd · 2026-07-29