Threat Intelligence / CVE / CVE-2023-44487

CVE-2023-44487 — Siemens Simatic S7-1500 Cpu 1518f-4 Pn/dp Mfp Firmware

CISA KEV
CVSS v3.1 7.5 (HIGH) · EPSS 99.9% (higher than 99.9% of all scored CVEs) · Priority 9/10 · Published 2023-10-10

As of 2026-07-14, CVE-2023-44487 is a HIGH-severity vulnerability in Siemens Simatic S7-1500 Cpu 1518f-4 Pn/dp Mfp Firmware, CVSS v3.1 7.5, EPSS 99.9% (99.9th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-10-10), with a US federal remediation deadline of 2023-10-31. Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2023-44487, most recently “Multiple Fortinet FortiOS Vulnerabilities (incl. CVE-2024-23113) Affect Siemens RUGGEDCOM APE1808 via Bundled Fortinet NGFW < V7.4.3 (SSA-832273)”.

Last updated: 2026-07-14

What is CVE-2023-44487?

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.

The record classifies CVE-2023-44487 under weakness class CWE-400. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on availability. 30 affected-product entries are recorded, across 9 vendors, listed below. The identifier was first published 1076 days ago.

Severity and exploitation probability

CVSS v3.1 base score
7.5 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (FIRST)
99.9% probability of exploitation in the next 30 days, higher than 99.9% of all scored CVEs
CISA KEV
Listed since 2023-10-10, federal remediation deadline 2023-10-31
Threadlinqs priority
9/10 — CISA KEV-listed, which Threadlinqs floors at 9
Published
2023-10-10, last modified 2026-07-14

Is CVE-2023-44487 being exploited?

CISA added CVE-2023-44487 to the Known Exploited Vulnerabilities catalog on 2023-10-10, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2023-10-31 under BOD 22-01. Weaponised exploit code for CVE-2023-44487 is publicly available. 11 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 43 in the Threadlinqs vulnerability feed.

Affected products and versions

Showing 25 of 30 recorded product entries.

How to fix CVE-2023-44487

The record marks a vendor fix as available for CVE-2023-44487. Patch reference: https://cgit.freebsd.org/ports/commit/?id=c64c329c2c1752f46b73e3e6ce9f4329be6629f9. Vendor advisory: https://access.redhat.com/security/cve/cve-2023-44487. Because CVE-2023-44487 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2023-10-31. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2023-44487

2 tracked threats in the Threadlinqs corpus reference CVE-2023-44487, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Showing 5 of 20 recorded references.

Full detection coverage & IOCs for threats exploiting CVE-2023-44487 are available via the Threadlinqs MCP server (Purple tier). View plans →

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