CVE-2025-27377Network attack vector

Credential disclosure via unvalidated self-signed certificates

Published Jan 22, 2026 · Updated Jan 22, 2026

Improper certificate validation in Altium Designer 24.9 through 25.1 allows man-in-the-middle attackers to read cloud traffic. Cloud connections accept a self-signed server certificate without validating its trust, allowing an intercepted session to terminate at an attacker-controlled endpoint. The attacker must control the network path and induce a cloud connection; interception exposes authentication credentials or design data, with no reported integrity or availability impact.

CVSS severity5.3
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in Altium Designer 24.9 through 25.1 allows man-in-the-middle attackers to read cloud traffic. Cloud connections accept a self-signed server certificate without validating its trust, allowing an intercepted session to terminate at an attacker-controlled endpoint. The attacker must control the network path and induce a cloud connection; interception exposes authentication credentials or design data, with no reported integrity or availability impact.

The record

CVE
CVE-2025-27377
Published
Jan 22, 2026
Updated
Jan 22, 2026
Vendor
Altium
Product
Altium Designer
Classifications
CWE-295, CAPEC-94, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 22, 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=24.9 <=25.1 changes=[{"at":"25.2","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Altium · Altium Designerversion=24.9 <=25.1 changes=[{"at":"25.2","status":"unaffected"}]

Published CVSS scores

5.3AltiumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/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-295Improper Certificate Validation
CAPEC-94Man-in-the-Middle Attack
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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