Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2023-44487

Cloud Platform Denial of Service

Google / Cloud Platform · 2.0

Watch CVE-2023-44487 Browse KEV feed
Severity
CVSS 7.5 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
100.0%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2023-44487 is an unauthenticated vulnerability affecting Google Cloud Platform. The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Google / Cloud Platform 2.0.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Cloud Platform Denial of Service

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.

ietf Affected
http
2.0
Siemens Affected
RUGGEDCOM APE1808
Before *
Siemens Affected
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
Before *
Siemens Affected
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
Before *
Siemens Affected
SINEC NMS
Before V3.0
Siemens Affected
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Before *
View vendor advisory (opens in new tab)
Published
10 Oct 2023
Exploitation Reported
10 Oct 2023
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

cisa nessus_scanner

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 10 Oct 2023

A trusted third party reported exploitation.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

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Source Added
CISA First 2023-10-10 00:00 UTC
CVE 2026-06-05 09:28 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nessus https://www.tenable.com/plugins/nessus/237067 02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.5 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

100.0%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Uncontrolled Resource Consumption CWE-400

Recent mention · Github Advisory Database (Maven)

[io.netty:netty-codec-http2] Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced

Impact DefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application...

Read full advisory

Timeline

From disclosure to observed exploitation

  1. 09:28 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  2. 09:26 UTC

    Nessus plugin available

    Scanner coverage available

  3. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  4. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2023-44487

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2023-44487",
  "confidence": "Confirmed",
  "cvss_score": 7.5,
  "cvss_estimated": false,
  "epss_score": 0.99999,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}