Security readout for executives and security teams
Plain-English summary
CVE-2023-44487 is the HTTP/2 “Rapid Reset” denial-of-service issue. Attackers abused normal request cancellation behavior to make servers consume resources at extreme rates, disrupting availability. It was exploited in the wild from August through October 2023 and is marked in KEV, so internet-facing HTTP/2 services deserve priority review.
Executive priority
Treat this as a high-priority availability risk for public digital services. It is not a breach indicator by itself, but successful exploitation can degrade or take down customer-facing platforms. Prioritize exposed HTTP/2 paths and vendor remediation confirmation.
Technical view
The flaw is protocol-level resource exhaustion: clients can rapidly create and cancel many HTTP/2 streams, causing server-side work without equivalent attacker cost. CVSS is 7.5 with network access, low complexity, no privileges, and high availability impact. Affected exposure depends on each HTTP/2 implementation and front-end architecture.
Likely exposure
Organizations exposing HTTP/2 through public websites, APIs, reverse proxies, load balancers, CDNs, service meshes, or application servers may be exposed. The bundle does not provide a single vendor/product list, so scope must be determined from HTTP/2 usage and applicable vendor advisories.
Exploitation context
Active exploitation is supported by KEV status and the CVE description. Cloudflare and Google reported large-scale HTTP/2 Rapid Reset DDoS activity in 2023. The sources describe availability attacks, not data theft or code execution.
Researcher notes
Evidence points to a broad protocol behavior rather than one named product. Avoid assuming exposure from the CVE record alone; validate HTTP/2 enablement, front-end termination points, and implementation-specific advisories. The source bundle includes vendor and project references but incomplete normalized affected CPE data.
Mitigation direction
- Inventory all internet-facing services and intermediaries that negotiate HTTP/2.
- Apply vendor updates or configuration guidance for each HTTP/2 component in scope.
- Confirm CDN, WAF, and DDoS protections include HTTP/2 Rapid Reset handling.
- Review vendor advisories before disabling HTTP/2 as a temporary risk decision.
- Monitor for abnormal HTTP/2 reset and stream churn patterns.
Validation and detection
- Check public endpoints for HTTP/2 support and map the serving component chain.
- Review edge, proxy, and application logs for reset-heavy HTTP/2 traffic.
- Verify deployed versions against vendor advisories referenced in the bundle.
- Confirm DDoS provider or cloud edge mitigations are enabled and documented.
- Run only approved, non-destructive availability validation in controlled environments.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-44487 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2023-44487 added to CISA KEV
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2023-10-10T00:00:00.000Z: CVE-2023-44487 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/dotnet/core/blob/e4613450ea0da7fd2fc6b61dfb2c1c1dec1ce9ec/release-notes/6.0/6.0.23/6.0.23.md?plain=1#L73CVE reference, mitre
- https://blog.cloudflare.com/technical-breakdown-http2-rapid-reset-ddos-attack/CVE reference, mitre
- https://aws.amazon.com/security/security-bulletins/AWS-2023-011/CVE reference, mitre
- https://cloud.google.com/blog/products/identity-security/how-it-works-the-novel-http2-rapid-reset-ddos-attackCVE reference, mitre
- https://www.nginx.com/blog/http-2-rapid-reset-attack-impacting-f5-nginx-products/CVE reference, mitre
- https://cloud.google.com/blog/products/identity-security/google-cloud-mitigated-largest-ddos-attack-peaking-above-398-million-rps/CVE reference, mitre
- https://news.ycombinator.com/item?id=37831062CVE reference, mitre
- https://blog.cloudflare.com/zero-day-rapid-reset-http2-record-breaking-ddos-attack/CVE reference, mitre
- https://www.phoronix.com/news/HTTP2-Rapid-Reset-AttackCVE reference, mitre
- https://github.com/envoyproxy/envoy/pull/30055CVE reference, mitre
- https://github.com/haproxy/haproxy/issues/2312CVE reference, mitre
- https://github.com/eclipse/jetty.project/issues/10679CVE reference, mitre
- https://forums.swift.org/t/swift-nio-http2-security-update-cve-2023-44487-http-2-dos/67764CVE reference, mitre
- https://github.com/nghttp2/nghttp2/pull/1961CVE reference, mitre
- https://github.com/netty/netty/commit/58f75f665aa81a8cbcf6ffa74820042a285c5e61CVE reference, mitre
- https://github.com/alibaba/tengine/issues/1872CVE reference, mitre
- https://github.com/apache/tomcat/tree/main/java/org/apache/coyote/http2CVE reference, mitre
- https://news.ycombinator.com/item?id=37830987CVE reference, mitre
- https://news.ycombinator.com/item?id=37830998CVE reference, mitre
- https://github.com/caddyserver/caddy/issues/5877CVE reference, mitre
- https://www.bleepingcomputer.com/news/security/new-http-2-rapid-reset-zero-day-attack-breaks-ddos-records/CVE reference, mitre
- https://github.com/bcdannyboy/CVE-2023-44487CVE reference, mitre
- https://github.com/grpc/grpc-go/pull/6703CVE reference, mitre
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.