CVE-2026-4751
Received Received - Intake
NULL Pointer Dereference in tmate Before 2.4.0 Causes Crash

Publication date: 2026-03-24

Last updated on: 2026-03-24

Assigner: Government Technology Agency of Singapore Cyber Security Group (GovTech CSG)

Description
NULL Pointer Dereference vulnerability in tmate-io tmate.This issue affects tmate: before 2.4.0.
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Meta Information
Published
2026-03-24
Last Modified
2026-03-24
Generated
2026-06-16
AI Q&A
2026-03-24
EPSS Evaluated
2026-06-15
NVD
CVE-2026-4751
EUVD
EUVD-2026-14768
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
tmate-io tmate to 2.4.0 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-476 The product dereferences a pointer that it expects to be valid but is NULL.
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Executive Summary

CVE-2026-4751 is a NULL Pointer Dereference vulnerability in the tmate-io tmate software affecting versions before 2.4.0. This vulnerability arises from unsafe cloning of functions in the codebase, which can cause the program to dereference a NULL pointer, potentially leading to a crash or unexpected behavior.

The issue was addressed by applying a patch originally from the OpenBSD repository that ensures cloned functions are handled securely, preventing the unsafe conditions that lead to this vulnerability.

Impact Analysis

This vulnerability can cause the tmate application to crash or behave unexpectedly due to a NULL pointer dereference. While it does not directly impact confidentiality or integrity, it affects availability by potentially causing denial of service.

The CVSS score of 5.3 (medium severity) reflects that the vulnerability can be exploited remotely without privileges or user interaction, leading to application disruption.

Compliance Impact

I don't know

Detection Guidance

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Mitigation Strategies

To mitigate the NULL Pointer Dereference vulnerability in tmate versions before 2.4.0, you should update tmate to version 2.4.0 or later where the issue has been fixed.

The fix involves applying a patch that secures the handling of cloned functions in the codebase, as done in the pull request merged on March 9, 2026.

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