CVE-2023-44487

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as…

Browse: All 2023 CVEs · All vendors

CVSS score: 7.5 High
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA KEV: Yes — actively exploited (added 2023-10-10, remediation due 2023-10-31)
Weakness (CWE): CWE-400
Published: 2023-10-10
Last modified: 2026-08-11
NVD status: Analyzed

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 products

siemens simatic s7-1500 cpu 1518f-4 pn\/dp mfp firmware
siemens sinec ins
siemens sinec nms
siemens st7 scadaconnect
siemens ruggedcom ape1808 firmware
siemens simatic s7-1500 cpu 1518-4 pn\/dp mfp firmware
siemens siplus s7-1500 cpu 1518-4 pn\/dp mfp firmware
ietf http
nghttp2 nghttp2
netty netty
envoyproxy envoy
eclipse jetty

Affected ranges per NVD CPE data; confirm exact versions in the vendor advisory.

Required action (CISA)

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Federal remediation deadline: 2023-10-31.

How to prioritize this

This vulnerability is on the CISA KEV list, meaning it is being actively exploited — treat it as urgent regardless of the raw CVSS number. Use the live CVE lookup for the latest NVD data, and the CVSS 3.1 calculator to model your own environmental score.

References

FAQ

Is CVE-2023-44487 actively exploited?

Yes. CISA added CVE-2023-44487 to its Known Exploited Vulnerabilities (KEV) catalog on 2023-10-10, with a federal remediation deadline of 2023-10-31. A KEV listing means real-world exploitation is confirmed, so patching this should be prioritized above many higher-CVSS bugs that aren't being exploited.

What is the CVSS score of CVE-2023-44487?

CVE-2023-44487 has a CVSS base score of 7.5 (High). Its vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Related vulnerabilities

Data source: NVD & CISA KEV. Shown as-is; nothing added. Last generated from NVD data — re-check the live tool for updates.