VulnerabilityPublished 13 Mar 2026

CVE-2026-3873: syslink software Avantra · Use of Hard-coded Credentials

Affects syslink software AvantraSource CVE Database V5

Compare

Not known to be exploited · CVSS 7.2 High : upgrade to 25.3.0 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

7.2High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 25.3.0

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
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: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 13 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 30 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 syslink software Avantra to 25.3.0.

Affected software

Product	Affected	Fixed in
syslink software AGAvantra	Affected <25.3.0	Fixed in 25.3.0

AI-suggested

Immediately restrict network access to Avantra management interfaces by implementing strict firewall rules and network segmentation to limit exposure to trusted administrators only.
If possible, identify and change or disable any hard-coded credentials within the Avantra deployment, or apply configuration changes to override default credentials.
Monitor logs and network traffic for unusual access patterns or unauthorized attempts to access Avantra functionalities.
Engage with syslink software AG for official patches or updates addressing this vulnerability and apply them promptly once available.
Implement multi-factor authentication (MFA) on access points to Avantra where feasible to add an additional security layer.
Conduct a thorough security review of all automation workflows managed by Avantra to detect any unauthorized changes or suspicious activities.
Educate IT and security teams about the risks associated with hard-coded credentials and enforce secure credential management practices in future deployments.

Description

Use of Hard-coded Credentials vulnerability in Avantra allows Accessing Functionality Not Properly Constrained by ACLs. This issue affects Avantra: before 25.3.0.

Impact

The exploitation of CVE-2026-3873 can lead to unauthorized access to Avantra's management functions, potentially allowing attackers to manipulate IT automation workflows, access sensitive configuration data, or escalate privileges within enterprise environments. This can compromise the confidentiality of sensitive operational data and the integrity of automated processes, potentially causing misconfigurations or unauthorized changes. Although availability is not directly impacted, the indirect effects of unauthorized changes could disrupt IT operations. Organizations relying on Avantra for critical infrastructure monitoring and automation are at risk of operational disruptions and data breaches. The ease of exploitation without authentication and user interaction increases the likelihood of attacks, especially in environments where Avantra management interfaces are exposed or insufficiently segmented. The lack of known exploits in the wild suggests limited current exploitation but does not reduce the urgency for remediation given the vulnerability's nature and potential impact.

CWE-798Use of Hard-coded Credentials (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product contains hard-coded credentials, such as a password or cryptographic key.
Architecture and Design
For outbound authentication: store passwords, keys, and other credentials outside of the code in a strongly-protected, encrypted configuration file or database that is protected from access by all outsiders, including other local users on the same system. Properly protect the key (CWE-320).
Architecture and Design
For inbound authentication: Rather than hard-code a default username and password, key, or other authentication credentials for first time logins, utilize a "first login" mode that requires the user to enter a unique strong password or key.
Architecture and Design
If the product must contain hard-coded credentials or they cannot be removed, perform access control checks and limit which entities can access the feature that requires the hard-coded credentials. For example, a feature might only be enabled through the system console instead of through a network connection.
OWASP Cheat Sheets
Key Management (opens in a new tab)
REST Security (opens in a new tab)
JSON Web Token for Java (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V2.10.4 (opens in a new tab)
V6.4.1 (opens in a new tab)
V3.5.2 (opens in a new tab)
Attack patterns
Read Sensitive Constants Within an Executable (opens in a new tab)
Try Common or Default Usernames and Passwords (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

support.avantra.com/hc/en-us/articles/5352465121695-Security-Notice-Legacy-Built-In-User-Account-rtm (opens in a new tab)

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Mar 2026, 08:44 UTC

WeaknessesCWE-798

Technical details

References

Community reviews

Related threats