CVE intelligence

CVE-2023-28320

Vulnerability intelligence

Published May 26, 2023Sources checked Oct 29, 2026

5.9MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2023-28320 and is rated Medium severity with a CVSS score of 5.9. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Aug 17, 2026

Vendor remediation details

CBL-Mariner Releases

Vendor-listed releases

1.72.0-2
8.0.34-1
8.2.1-1
3.21.4-11
2.16.1-1
3.28.2-1

CISA KEVNot listedBased on the latest collected catalog

EPSS2.7%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2023-28320?

A denial of service vulnerability exists in curl <v8.1.0 in the way libcurl provides several different backends for resolving host names, selected at build time. If it is built to use the synchronous resolver, it allows name resolves to time-out slow operations using `alarm()` and `siglongjmp()`.

When doing this, libcurl used a global buffer that was not mutex protected and a multi-threaded application might therefore crash or otherwise misbehave.

Source: NVD