VulnerabilityPublished 22 Jan 2026

CVE-2025-27377: Altium Designer · – Improper Certificate Validation

Affects Altium DesignerSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 25.2 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 8% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 25.2

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Altium Designer to 25.2.

Affected software

Product	Affected	Fixed in
AltiumAltium Designer	Affected >=24.9 <25.2	Fixed in 25.2

AI-suggested

Avoid connecting Altium Designer to cloud services over untrusted or public networks without additional protections.
Use VPNs or secure tunnels to encrypt traffic and reduce the risk of MITM attacks.
Monitor network traffic for unusual patterns or signs of interception, such as unexpected certificate changes or anomalies in cloud connection behavior.
Educate users to be cautious about prompts requiring interaction during cloud connection establishment.
Implement network segmentation and strict access controls to limit attacker positioning opportunities.
Regularly check for and apply vendor patches or updates addressing this vulnerability once released.
Consider using alternative secure communication methods or tools that enforce strict certificate validation until the vulnerability is resolved.
Conduct security assessments and penetration tests focusing on cloud communication security in engineering environments.

Description

CVE-2025-27377 is a medium-severity vulnerability in Altium Designer version 24.9.0 involving improper validation of self-signed server certificates during cloud connections. This flaw allows an attacker capable of man-in-the-middle (MITM) attacks to intercept or manipulate network traffic, potentially exposing authentication credentials or sensitive design data. Exploitation requires network access and user interaction, with a higher attack complexity. No known exploits are currently reported in the wild. The vulnerability impacts confidentiality but not integrity or availability. European organizations using Altium Designer for PCB design and engineering could face data exposure risks, especially in countries with significant electronics and manufacturing sectors. Mitigation involves avoiding untrusted networks, using VPNs, monitoring network traffic for anomalies, and applying vendor patches once available. Countries like Germany, France, Italy, and the UK are most likely affected due to their strong electronics industries and Altium user base.

Impact

For European organizations, the primary impact of CVE-2025-27377 is the potential exposure of sensitive design data and authentication credentials due to intercepted cloud communication. This can lead to intellectual property theft, loss of competitive advantage, and potential regulatory compliance issues under GDPR if personal data or sensitive business information is leaked. The vulnerability does not directly affect system integrity or availability but compromises confidentiality, which is critical in industries such as electronics manufacturing, automotive, aerospace, and defense sectors prevalent in Europe. Organizations using Altium Designer in collaborative cloud environments are particularly at risk if attackers can position themselves on the network path, such as in public or unsecured networks. The medium severity score reflects the need for caution but also indicates that exploitation is not trivial, requiring user interaction and a high level of attacker capability. Nonetheless, the risk to European supply chains and innovation ecosystems is notable given the widespread use of Altium Designer in engineering workflows.

Summary

CVE-2025-27377 is a vulnerability categorized under CWE-295 (Improper Certificate Validation) affecting Altium Designer version 24.9.0. The issue arises because the software does not properly validate self-signed server certificates when establishing cloud connections. This improper validation allows an attacker positioned to perform a man-in-the-middle (MITM) attack to intercept or manipulate the network traffic between the client and the cloud server. The attacker could exploit this to capture sensitive information such as authentication credentials or proprietary design data transmitted over the connection. The vulnerability has a CVSS v3.1 base score of 5.3, indicating medium severity. The vector string (AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N) shows that the attack is network-based but requires user interaction and has high attack complexity, with no privileges required and impacts confidentiality but not integrity or availability. No public exploits are known at this time, and no patches have been released yet. The vulnerability is significant for organizations relying on Altium Designer for critical PCB design workflows, especially when using cloud services for collaboration or storage. Attackers exploiting this flaw could gain unauthorized access to sensitive intellectual property or credentials, potentially leading to further compromise or espionage.

CWE-295Improper Certificate Validation (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not validate, or incorrectly validates, a certificate.
Architecture and Design · Implementation
Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
Implementation
If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
TLS Cipher String (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V9.2.1 (opens in a new tab)
V1.9.2 (opens in a new tab)
V2.8.5 (opens in a new tab)
Attack patterns
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

altium.com/platform/security-compliance/security-advisories (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jan 2026, 08:52 UTC

WeaknessesCWE-295

Technical details

References

Community reviews

Related threats