[UPDATE] [medium] HTTP/2: Multiple vulnerabilities allow Denial of Service

CSIRTS triage

What

A remote, anonymous attacker can exploit vulnerabilities in various http/2 implementations to conduct a Denial of Service attack.

Who is affected

Deployments using HTTP/2 implementations are affected.

Urgency

Remediation is medium urgency as the vulnerabilities can lead to Denial of Service but are not currently exploited.

Action

Update HTTP/2 implementations to the latest versions.

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

Details

Source

CERT-Bund (BSI) Security Advisories (DE · national-cert · site)

Severity

medium

Published

2026-07-03

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-2024-0789

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.

• Exploitation likely imminentCVE-2023-45288EPSS puts this in the most-targeted tier (92.0% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-2653EPSS puts this in the most-targeted tier (83.2% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-27316EPSS puts this in the most-targeted tier (91.3% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-2758EPSS puts this in the most-targeted tier (72.8% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 99% of all scored CVEs.
• Exploitation likely imminentCVE-2024-27919EPSS puts this in the most-targeted tier (86.7% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-28182EPSS puts this in the most-targeted tier (85.0% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-30255EPSS puts this in the most-targeted tier (87.8% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.
• Exploitation likely imminentCVE-2024-31309EPSS puts this in the most-targeted tier (94.6% 30-day exploitation probability). Prioritize alongside KEV items. Riskier than 100% of all scored CVEs.

Referenced CVEs

Recent advisories for HTTP/2

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.

• highCVE-2026-55213: h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit edd7a120bf…nvd · 2026-07-10
• high[UPDATE] [high] HTTP/2 implementations: Vulnerability allows denial of servicecert-bund · 2026-07-09
• highGHSA-659f-rgp5-w4wf: Skipper: opaAuthorizeRequestWithBody filter bypasses OPA policy on Transfer-Encoding — ch…ghsa · 2026-07-08
• high[UPDATE] [high] http/2 implementations: Vulnerability allows denial of servicecert-bund · 2026-07-06
• criticalCVE-2026-10536: A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stre…nvd · 2026-07-03
• criticalCVE-2026-10536: HTTP/2 stream-dependency tree UAFmsrc · 2026-07-02

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