CVE-2026-4751
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
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| tmate-io | tmate | to 2.4.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-476 | The product dereferences a pointer that it expects to be valid but is NULL. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
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.
How can this vulnerability impact me? :
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.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
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.