Yamcs has No Rate Limiting on Authentication Endpoint

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-44596: 2.06% estimated exploitation activity in the next 30 days; percentile 81.35 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The authentication endpoint POST /auth/token in yamcs-core lacks any form of rate limiting, account lockout, or failed attempt throttling. As a result, an unauthenticated remote attacker can perform unlimited password guessing attempts against any user account. This missing rate limiting vulnerability (CWE-307) significantly increases the risk of successful brute-force attacks. Root Cause File: yamcs-core/src/main/java/org/yamcs/http/auth/AuthHandler.java POST /auth/token has no rate limiting, no lockout after failed attempts, and no CAPTCHA. The handler processes unlimited authentication requests without any throttling mechanism: This is absent by default — the official quickstart and documentation contain no guidance on configuring rate limiting. Impact An attacker can make unlimited authentication attempts against any account. This enables efficient brute-force attacks against any account. Proof of Concept Confirmed: 20 attempts in 0.07 seconds, no rate limiting enforced.…

Published by the source

27 May 2026, 00:04 UTC

Last modified by the source

27 May 2026, 00:04 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-w5r6-mcgq-7pq4

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# Patch Next advisory brief: CVE-2026-44596

Advisory: Yamcs has No Rate Limiting on Authentication Endpoint
IDs: CVE-2026-44596, GHSA-w5r6-mcgq-7pq4
Record: https://patchnext.com/advisories/cve-2026-44596 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.yamcs:yamcs-core 5.12.7. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.yamcs:yamcs-core: affected < 5.12.7; fixed in 5.12.7

## Suggested inspection (read-only)
- Maven org.yamcs:yamcs-core: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.yamcs:yamcs-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-w5r6-mcgq-7pq4 (GitHub-reviewed advisory GHSA-w5r6-mcgq-7pq4 lists affected ranges: Maven org.yamcs:yamcs-core >=0 <5.12.7)

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