CVE intelligence

CVE-2026-86409

Vulnerability intelligence

Published Oct 20, 2026Sources checked Oct 20, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-86409. 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: Oct 19, 2026

USN-8927-1 fixed vulnerabilities in curl.

CISA KEVNot listedBased on the latest collected catalog

EPSSUnavailableNo current score collected

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-86409?

Setting `CURLOPT_AWS_SIGV4` to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an `Authorization: AWS4-HMAC-SHA256` header to whatever URL isset next, leaking state information.

Source: NVD