Time-of-check Time-of-use (TOCTOU) Affecting netty-tcnative package, versions <2.0.80-150200.3.48.1


Severity

Recommended
0.0
high
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-SLES155-NETTYTCNATIVE-18533068
  • published5 Aug 2026
  • disclosed4 Aug 2026

Introduced: 4 Aug 2026

CVE-2026-56822  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade SLES:15.5 netty-tcnative to version 2.0.80-150200.3.48.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream netty-tcnative package and not the netty-tcnative package as distributed by SLES. See How to fix? for SLES:15.5 relevant fixed versions and status.

Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, the OcspServerCertificateValidator forwards the SslHandshakeCompletionEvent before the asynchronous OCSP validation completes. This allows the client's downstream handlers to send sensitive application data (e.g., HTTP requests) to a revoked server before the channel is closed by the OCSP check. n io.netty.handler.ssl.ocsp.OcspServerCertificateValidator#userEventTriggered, when an SslHandshakeCompletionEvent is received, the validator immediately calls ctx.fireUserEventTriggered(evt). It then initiates an asynchronous OCSP query using OcspClient.query. Because the handshake completion event is forwarded immediately, downstream handlers in the client's pipeline are notified that the TLS handshake is successful. They may then begin reading and processing incoming application data or sending outgoing data. If the OCSP response later indicates the server's certificate is REVOKED, the validator closes the channel, but by this time, the client may have already leaked sensitive data to a revoked server or processed malicious responses from it. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

CVSS Base Scores

version 3.1