How severe is CVE-2023-44487?

CVE-2023-44487 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-44487?

CVE-2023-44487 affects the following packages: golang.org/x/net (Go), org.apache.tomcat:tomcat-coyote (Maven), org.apache.tomcat:tomcat-coyote (Maven), org.apache.tomcat:tomcat-coyote (Maven), org.apache.tomcat:tomcat-coyote (Maven), org.apache.tomcat.embed:tomcat-embed-core (Maven), org.apache.tomcat.embed:tomcat-embed-core (Maven), org.apache.tomcat.embed:tomcat-embed-core (Maven), and 14 more. Ecosystems affected: Go, Maven, SwiftURL.

How do I fix CVE-2023-44487?

Update golang.org/x/net to 0.17.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-44487 is resolved across your whole dependency graph.

How do I detect CVE-2023-44487 in my Go, Maven, SwiftURL dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2023-44487 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2023-44487?

O3 pinpoints whether CVE-2023-44487 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2023-44487 actively exploited in the wild?

Yes. There are 20 known exploit references for CVE-2023-44487, including 1 documented proof-of-concept exploit on Exploit-DB and 12 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-44487?

CVE-2023-44487 has an EPSS (Exploit Prediction Scoring System) score of 100.0%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is CVE-2023-44487 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2023-44487 (HTTP/2 Rapid Reset Attack Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2023-10-10. CISA required all US federal civilian agencies to remediate this vulnerability by 2023-10-31. The required action was: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

What type of vulnerability is CVE-2023-44487?

CVE-2023-44487 is classified as Uncontrolled Resource Consumption (CWE-400). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-44487 published, and has it been updated?

CVE-2023-44487 was published on October 10, 2023 and was last updated on July 23, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CISA KEV·Added 2023-10-10 — agencies required to remediate by 2023-10-31

🐹 Go☕ Maven📦 SwiftURL

CVE-2023-44487

HIGH

HTTP/2 Stream Cancellation Attack

Also known asBIT-apisix-2023-44487BIT-aspnet-core-2023-44487BIT-contour-2023-44487BIT-dotnet-2023-44487BIT-dotnet-sdk-2023-44487BIT-envoy-2023-44487

Published

Oct 10, 2023

Updated

Jul 23, 2026

Affected

22 pkgs

Patched

21 / 22

Exploits

20 known

EPSS Exploitation Probability

via FIRST.org ↗

100.0%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

22 pkgs affected

🐹golang.org/x/net☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat:tomcat-coyote☕org.apache.tomcat.embed:tomcat-embed-core☕org.apache.tomcat.embed:tomcat-embed-core☕org.apache.tomcat.embed:tomcat-embed-core+14 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go, Maven packages — download data is not available via public APIs for these ecosystems.

Description

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

Affected Packages

22 total 21 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`golang.org/x/net`	all versions	0.17.0
☕Maven	`org.apache.tomcat:tomcat-coyote`	≥ 11.0.0-M1&&< 11.0.0-M12	11.0.0-M12
☕Maven	`org.apache.tomcat:tomcat-coyote`	≥ 10.0.0&&< 10.1.14	10.1.14
☕Maven	`org.apache.tomcat:tomcat-coyote`	≥ 9.0.0&&< 9.0.81	9.0.81
☕Maven	`org.apache.tomcat:tomcat-coyote`	≥ 8.5.0&&< 8.5.94	8.5.94
☕Maven	`org.apache.tomcat.embed:tomcat-embed-core`	≥ 11.0.0-M1&&< 11.0.0-M12	11.0.0-M12

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-52426remotemultiple

HTTP/2 2.0 - Denial Of Service (DOS)

by Madhusudhan Rajappa · Sep 16, 2025

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for golang.org/x/net. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update golang.org/x/net to 0.17.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-44487 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2023-44487 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2023-44487. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

O3 Security · Impact-Aware SCA

Is CVE-2023-44487 in your dependencies?

O3 detects CVE-2023-44487 across Go, Maven, SwiftURL dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works