sirupsen logrus up to 1.8.2/1.9.2 Entry.Writer denial of service

Summaryinfo

A vulnerability has been found in sirupsen logrus up to 1.8.2/1.9.2 and classified as problematic. Affected by this issue is the function Entry.Writer. The manipulation leads to denial of service. This vulnerability is traded as CVE-2025-65637. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, has been found in sirupsen logrus up to 1.8.2/1.9.2. This issue affects the function Entry.Writer. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

A denial-of-service vulnerability exists in github.com/sirupsen/logrus when using Entry.Writer() to log a single-line payload larger than 64KB without newline characters. Due to limitations in the internal bufio.Scanner, the read fails with "token too long" and the writer pipe is closed, leaving Writer() unusable and causing application unavailability (DoS). This affects versions < 1.8.3, 1.9.0, and 1.9.2. The issue is fixed in 1.8.3, 1.9.1, and 1.9.3+, where the input is chunked and the writer continues to function even if an error is logged.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2025-65637 since 11/18/2025. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 277513 (Linux Distros Unpatched Vulnerability : CVE-2025-65637), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.8.3 or 1.9.3 eliminates this vulnerability. The upgrade is hosted for download at github.com. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (277513), EUVD (EUVD-2025-201258) and CERT Bund (WID-SEC-2026-0114). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• Fedora Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Red Hat OpenShift

Productinfo

Vendor

• sirupsen

Name

• logrus

Version

• 1.8.0
• 1.8.1
• 1.8.2
• 1.9.0
• 1.9.1
• 1.9.2

Website

• Product: https://github.com/sirupsen/logrus/

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