Avantra: Use of Hard-coded Credentials
CVE-2026-3873 is a high-severity use of hard-coded credentials vulnerability in Avantra from Syslink Software, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 25.3.0 as the first without the flaw, so updating Avantra to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.23% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Avantra to 25.3.0 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Syslink Software | Avantra | before 25.3.0 | 25.3.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N. Scored by CNA (ncsc.ch).
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Hard-coded Credentials
The product contains hard-coded credentials, such as a password or cryptographic key.
How developers prevent this class of flaw
- 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). If you cannot use encryption to protect the file, then make sure that the permissions are as restrictive as possible. In Windows environments, the Encrypted File System (EFS) may provide some protection.
- 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.
- 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.
More Use of Hard-coded Credentials vulnerabilities (CWE-798)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Avantra
- 9.1 Critical severity
- 7.5 High severity
- 9.6 Critical severity
Recent Use of Hard-coded Credentials vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 7.3 High severity
- 7.8 High severity
- 9.8 Critical severity
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