Akka.Remote TLS did not properly implement certificate-based authentication

Exploitation

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

CVSS 4.0

9.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2025-61778: 0.31% estimated exploitation activity in the next 30 days; percentile 23.74 (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.

Impact This is a critical network security vulnerability for Akka.Remote users who have SSL / TLS enabled on their Akka.Remote connections and were expecting certificate-based authentication to be enforced on all peers attempting to join the network. In all versions of Akka.Remote from v1.2.0 to v1.5.51, TLS could be enabled via our akka.remote.dot-netty.tcp transport and this would correctly enforce private key validation on the server-side of inbound connections. Akka.Remote, however, never asked the outbound-connecting client to present ITS certificate - therefore it's possible for untrusted parties to connect to a private key'd Akka.NET cluster and begin communicating with it without any certificate. The issue here is that for certificate-based authentication to work properly, ensuring that all members of the Akka.Remote network are secured with the same private key, Akka.Remote needed to implement mutual TLS. This was not the case before Akka.NET v1.5.52. If you are running…

Published by the source

7 Oct 2025, 21:15 UTC

Last modified by the source

7 Oct 2025, 21:15 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jhpv-4q4f-43g5

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# Patch Next advisory brief: CVE-2025-61778

Advisory: Akka.Remote TLS did not properly implement certificate-based authentication
IDs: CVE-2025-61778, GHSA-jhpv-4q4f-43g5
Record: https://patchnext.com/advisories/cve-2025-61778 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: akka.cluster 1.5.52; akka.remote 1.5.52. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet akka.cluster: affected >= 1.2.0, < 1.5.52; fixed in 1.5.52
- NuGet akka.remote: affected >= 1.2.0, < 1.5.52; fixed in 1.5.52

## Suggested inspection (read-only)
- NuGet akka.cluster: check the installed version with your package manager.
- NuGet akka.remote: 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 akka.cluster, akka.remote.
- 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-jhpv-4q4f-43g5 (GitHub-reviewed advisory GHSA-jhpv-4q4f-43g5 lists affected ranges: NuGet akka.remote >=1.2.0 =1.2.0 <1.5.52)

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