yamcs: Improper Restriction of Excessive Authentication Attempts
CVE-2026-44596 is a critical-severity improper restriction of excessive authentication attempts vulnerability in yamcs, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected yamcs versions: < 5.12.7. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.06% chance of exploitation within 30 days, higher than 82% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of yamcs you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
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
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.5 | Medium | CNA (github.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
Yamcs is a mission control framework. Prior to 5.12.7, the authentication endpoint POST /auth/token in yamcs-core, handled by yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java, lacked any rate limiting, account lockout, or failed-attempt throttling, so an unauthenticated remote attacker could perform unlimited password-guessing attempts against any user account, significantly increasing the risk of successful brute-force attacks. This issue is fixed in versions 5.12.7 and 5.13.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of Excessive Authentication Attempts
The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.
How developers prevent this class of flaw
- Common protection mechanisms include: Disconnecting the user after a small number of failed attempts Implementing a timeout Locking out a targeted account Requiring a computational task on the user's part.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
More Improper Restriction of Excessive Authentication Attempts vulnerabilities (CWE-307)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other vulnerabilities in yamcs
- 9.9 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 8.8 High severity
- 9.1 Critical severity
- 9.1 Critical severity
Recent Improper Restriction of Excessive Authentication Attempts vulnerabilities
- 8.3 High severity
- 7.5 High severity
- 7.5 High severity
- 7.3 High severity
- 7.1 High severity
- 7.5 High severity
Spotted an error? Tell us.