CVE-2025-66382

Processing delay via crafted XML input

Published Nov 28, 2025 · Updated Jul 14, 2026

Algorithmic complexity in Expat Project libexpat 2.7.5 and earlier allows local users to interrupt processing with crafted XML. The project has not disclosed which parser routine or XML construct performs the disproportionate work; a roughly 2 MiB file consumes 25–100 seconds of CPU time. The file must reach a local process that parses it with libexpat, and the documented consequence is temporary processing delay rather than a crash.

CVSS severity2.9
Low
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic complexity in Expat Project libexpat 2.7.5 and earlier allows local users to interrupt processing with crafted XML. The project has not disclosed which parser routine or XML construct performs the disproportionate work; a roughly 2 MiB file consumes 25–100 seconds of CPU time. The file must reach a local process that parses it with libexpat, and the documented consequence is temporary processing delay rather than a crash.

The record

CVE
CVE-2025-66382
Published
Nov 28, 2025
Updated
Jul 14, 2026
Vendor
Siemens
Product
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
Classifications
CWE-407, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 28, 2025CVE 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=V3.1.5 <*

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Siemens · SIPLUS S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*
Expat Project · libexpatversion=0 <=2.7.5
Siemens · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPversion=V3.1.5 <*
Siemens · RUGGEDCOM RST2428Pversion=0 <V4.0
Siemens · SIMATIC S7-1500 CPU 1518-4 PN/DP MFPversion=V3.1.5 <*

Published CVSS scores

2.9MITRE CNACVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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.

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No observations available

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

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

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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