CVE-2023-46219Network attack vector

HTTPS downgrade via HSTS file truncation

Published Dec 12, 2023 · Updated Jul 14, 2026

HSTS data handling in curl and affected Siemens products allows remote attackers to bypass enforced HTTPS after HSTS file truncation. The save function appends a suffix to the configured filename, creates a temporary file, and replaces the target after the suffixed name exceeds the filesystem limit, clearing stored HSTS entries. Reaching the flaw requires HSTS persistence with a near-limit filename; subsequent requests lack remembered HTTPS upgrade rules.

CVSS severity5.3
Medium
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HSTS data handling in curl and affected Siemens products allows remote attackers to bypass enforced HTTPS after HSTS file truncation. The save function appends a suffix to the configured filename, creates a temporary file, and replaces the target after the suffixed name exceeds the filesystem limit, clearing stored HSTS entries. Reaching the flaw requires HSTS persistence with a near-limit filename; subsequent requests lack remembered HTTPS upgrade rules.

The record

CVE
CVE-2023-46219
Published
Dec 12, 2023
Updated
Jul 14, 2026
Vendor
Siemens
Product
SINEC NMS
Classifications
CWE-311, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <V3.0 SP1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Siemens · SINEC NMSversion=0 <V3.0 SP1
Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
curl · curlversion=8.4.0 <=8.4.0

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-311Missing Encryption of Sensitive Data
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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