CVE-2026-118766
Description
A flaw was found in Botan. Its Online Certificate Status Protocol (OCSP) client improperly follows HTTP redirects when sending certificate validation requests. A malicious responder or network attacker can exploit this issue to redirect the client into making a blind request to an otherwise inaccessible internal service. This Server-Side Request Forgery (SSRF) flaw can allow attackers to interact with internal systems or infer internal service availability via response timing.
Statement
This vulnerability is rated as Moderate severity because exploitation is restricted to blind, single-request server-side request forgery without direct content exfiltration, requiring an adversarial certificate responder or an in-path attacker. Botan is not distributed as part of core Red Hat Enterprise Linux and is only consumed via community repositories such as EPEL. Risk is further constrained to applications that explicitly initiate online certificate revocation checks over unmanaged network paths.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
