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MEDIUM

Out-of-bounds read in HTTP client no_proxy handling

Published Sep 30, 2025

Description

Issue summary: An application using the OpenSSL HTTP client API functions may trigger an out-of-bounds read if the 'no_proxy' environment variable is set and the host portion of the authority component of the HTTP URL is an IPv6 address.

Impact summary: An out-of-bounds read can trigger a crash which leads to Denial of Service for an application.

The OpenSSL HTTP client API functions can be used directly by applications but they are also used by the OCSP client functions and CMP (Certificate Management Protocol) client implementation in OpenSSL. However the URLs used by these implementations are unlikely to be controlled by an attacker.

In this vulnerable code the out of bounds read can only trigger a crash. Furthermore the vulnerability requires an attacker-controlled URL to be passed from an application to the OpenSSL function and the user has to have a 'no_proxy' environment variable set. For the aforementioned reasons the issue was assessed as Low severity.

The vulnerable code was introduced in the following patch releases: 3.0.16, 3.1.8, 3.2.4, 3.3.3, 3.4.0 and 3.5.0.

The FIPS modules in 3.5, 3.4, 3.3, 3.2, 3.1 and 3.0 are not affected by this issue, as the HTTP client implementation is outside the OpenSSL FIPS module boundary.

Affected products

Remediation

Red Hat statement

This vulnerability was rated as Low severity because exploitation requires a very specific set of conditions: the application must pass an attacker-controlled IPv6 URL to the OpenSSL HTTP client functions, and the no_proxy environment variable must be set by the user. Even under these conditions, the issue can only lead to an out-of-bounds read resulting in a crash, causing an application level denial of service. There is no potential for information disclosure or remote code execution. Additionally, typical use cases of the OpenSSL HTTP client (e.g., in OCSP or CMP) do not involve attacker-controlled URLs, which further reduces the likelihood of exploitation.

Red Hat mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Metrics

Weaknesses (1)

CWE-125

Out-of-bounds Read

References (17)

Change history (0)

No recorded changes yet.

Sources
CVE.org / MITRE
Status PUBLISHED
Assigner openssl
Published Sep 30, 2025
Updated Jul 14, 2026
Reserved Aug 20, 2025
Link CVE-2025-9232
CISA Vulnrichment
Updated Sep 30, 2025
NVD
Status Deferred
Modified Jul 14, 2026
Link CVE-2025-9232
Red Hat
Severity Low
Public date Sep 30, 2025
Links CVE-2025-9232 - Bugzilla