CVE intelligence

CVE-2026-8458

Vulnerability intelligence

Published Jul 3, 2026Sources checked Oct 27, 2026

6.5MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-8458 and is rated Medium severity with a CVSS score of 6.5. 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

Ubuntu Security Notices guidance

Vendor revision: Sep 28, 2026

USN-8487-1 fixed vulnerabilities in curl.

Microsoft Security Response Center guidance

Vendor revision: Aug 13, 2026

CBL-Mariner Releases

Vendor-listed releases

8.11.1-10

CISA KEVNot listedBased on the latest collected catalog

EPSS0.4%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-8458?

libcurl might in some circumstances reuse the wrong connection when asked to do Negotiate-authenticated ones, even when they are set to use different "services".

libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead.

When reusing a connection a range of criteria must be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different services.

Source: NVD