[UPDATE] [high] http/2 implementations: Vulnerability allows denial of service
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
A remote, anonymous attacker can exploit a vulnerability in various http/2 implementations to carry out a denial of service attack.
CSIRTS triage
- What
- A vulnerability in various http/2 implementations allows for a denial of service attack.
- Who is affected
- Various http/2 implementations are affected.
- Urgency
- Remediation is urgent due to the high severity and active exploitation.
- Action
- Update http/2 implementations to the latest version.
AI-assisted analysis generated from the source advisory — verify against the original.
Details
Original advisory: https://wid.cert-bund.de/portal/wid/securityadvisory?name=WID-SEC-2023-2618
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 confirmedCVE-2023-44487Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 99.9% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2023-44487 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownexploitedMultiple vulnerabilities in IBM products (August 21, 2026)cert-fr-avis
- unknownexploitedMultiple vulnerabilities in IBM products (August 14, 2026)cert-fr-avis
- high[UPDATE] [high] Eclipse Jetty: Multiple vulnerabilities allow Denial of Servicecert-bund
- criticalexploitedGitLab Security Release: 16.5.1, 16.4.2, 16.3.6gitlab
- criticalexploitedGitLab Security Release: 16.5.1, 16.4.2, 16.3.6gitlab
- unknownexploitedJenkins Security Advisory 2023-10-18jenkins
- criticalexploitedCVE-2023-44487: HTTP/2 Rapid Reset Attack Vulnerabilitycisa-kev
Recent advisories for http/2 implementations
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] HTTP/2 implementations: Vulnerability allows denial of servicecert-bund · 2026-08-14
- mediumCVE-2026-71554: h2 is a pure-Python implementation of a HTTP/2 protocol stack. Versions up to and including 4.…nvd · 2026-08-06
- mediumCVE-2026-15713: A vulnerability was found in libsoup's HTTP/2 protocol implementation. The library fails to co…nvd · 2026-07-14
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