A vulnerability in curl allows unauthenticated attackers to potentially intercept sensitive cookies due to a failure in processing the Secure flag when specific whitespace characters are used.

This is an information exposure vulnerability (CWE-201) where the curl library incorrectly handles a tab character in a Set-Cookie header, causing the Secure attribute to be ignored and allowing the cookie to be sent over unencrypted HTTP. This flaw is remotely exploitable without authentication.

The potential for sensitive session cookies to be transmitted over plaintext HTTP creates a significant risk of credential theft and account takeover. With a CVSS score of 7.5, this high severity vulnerability could result in unauthorized access to user accounts or internal systems, causing severe reputational and data security consequences for organizations relying on curl for secure network communications.

Immediate Action: Organizations should monitor the official curl security advisories and update to the latest patched version of the curl library as soon as it becomes available.

Proactive Monitoring: Review web server and network proxy logs for unusual Set-Cookie header formatting patterns that deviate from standard specifications.

Compensating Controls: Implement strict transport security policies and ensure that all sensitive application traffic is forced over HTTPS, which may mitigate the risk of cookie exposure even if the client-side flag is stripped.

Public Exploit Available: Unknown

Given the potential for unauthorized access to sensitive session data, this vulnerability poses a high risk to application integrity. Security teams should prioritize identifying all instances of the affected curl versions within their infrastructure and verify their exposure to untrusted network traffic. Apply all security updates immediately upon release to ensure that cookie security flags are processed correctly and session data remains protected from interception.