Platform
dotnet
Component
akka.remote
Fixed in
1.2.1
1.5.52
CVE-2025-61778 is a critical network security vulnerability affecting Akka.Remote versions up to 1.5.9. This flaw allows attackers to bypass certificate-based authentication when using TLS, potentially leading to unauthorized access and control over the network. A fix is available in version 1.5.52, and users are strongly advised to upgrade immediately.
The core of this vulnerability lies in Akka.Remote's handling of TLS connections. While the server-side correctly validates client certificates, the outbound-connecting client is not required to present its own certificate. This means an attacker can establish a TLS-encrypted connection without proper authentication, effectively impersonating a legitimate peer. The impact is severe: an attacker could join the Akka.Remote network, intercept messages, inject malicious commands, and potentially compromise the entire system. This is particularly concerning in environments where Akka.Remote is used for critical inter-service communication, as it could lead to cascading failures and data breaches. The vulnerability's reliance on SSL/TLS means it's most impactful in environments where this encryption is actively used, which is common for securing sensitive data in transit.
This vulnerability was publicly disclosed on 2025-10-07. There is currently no indication of active exploitation in the wild, but the critical severity and ease of exploitation (requiring only a TLS connection) suggest it could become a target. The vulnerability's impact is amplified by its network-based nature, making it potentially exploitable from external sources. It is not currently listed on CISA KEV, but its severity warrants monitoring.
Exploit Status
EPSS
0.09% (25% percentile)
CISA SSVC
The primary mitigation is to upgrade Akka.Remote to version 1.5.52 or later, which includes the fix for this authentication bypass. If upgrading immediately is not possible, consider temporarily disabling TLS authentication on Akka.Remote connections. While this reduces security, it prevents the bypass vulnerability from being exploited. Alternatively, implement a WAF or proxy that enforces certificate validation on both inbound and outbound connections, effectively compensating for the missing client certificate requirement in Akka.Remote. Carefully review Akka.Remote configuration to ensure TLS is enabled and properly configured, and monitor logs for any suspicious connection attempts.
Update Akka.NET to version 1.5.52 or later. This version fixes the vulnerability by implementing mutual TLS (mTLS) by default, requiring both parties to have the same private key. If you cannot update immediately, avoid exposing the application publicly as a temporary measure.
Vulnerability analysis and critical alerts directly to your inbox.
CVE-2025-61778 is a critical vulnerability in Akka.Remote versions ≤1.5.9 that allows attackers to bypass certificate-based authentication over TLS, potentially gaining unauthorized network access.
If you are using Akka.Remote versions 1.2.0 through 1.5.9 and have SSL/TLS enabled, you are likely affected by this vulnerability. Upgrade to 1.5.52 or later to mitigate the risk.
The recommended fix is to upgrade Akka.Remote to version 1.5.52 or later. If immediate upgrade is not possible, consider temporarily disabling TLS authentication or implementing a compensating control like a WAF.
There is currently no confirmed evidence of active exploitation, but the vulnerability's severity and ease of exploitation suggest it could become a target.
Refer to the official Akka.Remote project website and related security advisories for the most up-to-date information and guidance regarding CVE-2025-61778.
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