CVE-2023-44487
DoS in Apache Tomcat 8.5.0 – 8.5.93
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-44487 is a high-severity Uncontrolled Resource Consumption (CWE-400) vulnerability in Apache Tomcat. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 0.0% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
The vulnerability CVE-2023-44487 is a denial-of-service flaw in the HTTP/2 protocol that stems from rapid request cancellation, which allows an attacker to reset many streams in quick succession and exhaust server resources. It affects any HTTP/2 server implementation that processes such cancellations without sufficient rate limiting or resource controls, and carries a CVSS 3.1 score of 7.5 reflecting high availability impact over a network with no authentication required.
Unauthenticated remote attackers can exploit the issue by sending a flood of HTTP/2 requests followed by immediate RST_STREAM frames, driving up CPU and memory consumption on the target server until it becomes unresponsive. The flaw was actively exploited in the wild between August and October 2023.
Multiple oss-security advisories referenced in the disclosure discuss vendor-specific patches and configuration changes to mitigate stream-reset abuse. The EPSS score has remained near its peak of 0.9450 with a current value of 0.9439, indicating sustained exploitation interest following public release.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-2795
Vulnerability Data
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.
- CWE(s)
- KEV Date Added
- 10 October 2023
Related Threats
Threat-Actor AttributionAI
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Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Limiting concurrent sessions directly prevents uncontrolled resource consumption by capping the number of active sessions per user or account.
Analysis identifies uncontrolled resource consumption indicative of denial-of-service or abuse attempts.
Contingency plan testing includes resource exhaustion scenarios to verify recovery, making it harder for attackers to sustain exploits that cause uncontrolled consumption.
Updated contingency plans include current procedures to detect, contain, and recover from resource exhaustion, limiting an attacker's ability to sustain impact from uncontrolled consumption.
Alternate site allows resumption of operations if resource exhaustion at the primary site is exploited to cause unavailability.
Alternate telecommunications services enable resumption of essential functions when primary services become unavailable due to uncontrolled resource consumption.
The team can analyze and respond to resource exhaustion incidents, reducing the impact of attacks that exploit uncontrolled consumption weaknesses.
Timely maintenance support and spare parts enable rapid recovery from failures induced by uncontrolled resource consumption, shortening the impact window of denial-of-service attacks.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Pre-agreed severity-based prioritization and resource allocation during incident triage reduce the likelihood that an attacker-induced resource exhaustion will overwhelm the organization before corrective action is taken.
Early notification of anomalous resource consumption or system malfunctions enables throttling or isolation before availability is lost.
Specifying log storage limits and rotation procedures reduces the risk that unbounded log growth will exhaust disk or memory resources and cause denial of service.
Resource-utilization monitoring and alerting on bottlenecks or overloads limits the impact of denial-of-service or resource-exhaustion attacks.
A.8.20 implements network-level protections (firewalls, segmentation, protocol hardening, monitoring, authentication of systems/devices) that can limit abuse of a resource-consuming weakness but do not stop the weakness from being exploitable; the flaw remains present in the product and can still be triggered from an authorized or internal context.
Monitoring network service usage and applying controls to restrict access when necessary limits an attacker’s ability to consume excessive resources through unrestricted or unauthenticated service calls.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-400, a class-level weakness. Rules are authored against its narrower children: CWE-770.