rust-openssl up to 0.10.78 X509Ref::ocsp_responders certificate validation

Summaryinfo

A vulnerability classified as problematic was found in rust-openssl up to 0.10.78. Affected is the function X509Ref::ocsp_responders. Executing a manipulation can lead to certificate validation. This vulnerability is registered as CVE-2026-42327. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in rust-openssl up to 0.10.78 and classified as problematic. This vulnerability affects the function X509Ref::ocsp_responders. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. CVE summarizes:

rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.7 to before 0.10.79, X509Ref::ocsp_responders returns OCSP responder URLs from a certificate's AIA extension as OpensslString, whose Deref<Target = str> wraps the raw bytes with str::from_utf8_unchecked. OpenSSL does not enforce that the underlying IA5String is ASCII, so a certificate with non-UTF-8 bytes in its OCSP accessLocation causes safe Rust code to construct a &str that violates the UTF-8 invariant — resulting in undefined behavior. This vulnerability is fixed in 0.10.79.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-42327 since 04/26/2026. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/19/2026). The MITRE ATT&CK project declares the attack technique as T1587.003.

The vulnerability scanner Nessus provides a plugin with the ID 314940 (Linux Distros Unpatched Vulnerability : CVE-2026-42327), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.10.79 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (314940). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Network Encryption Software

Name

• rust-openssl

Version

• 0.10.0
• 0.10.1
• 0.10.2
• 0.10.3
• 0.10.4
• 0.10.5
• 0.10.6
• 0.10.7
• 0.10.8
• 0.10.9
• 0.10.10
• 0.10.11
• 0.10.12
• 0.10.13
• 0.10.14
• 0.10.15
• 0.10.16
• 0.10.17
• 0.10.18
• 0.10.19
• 0.10.20
• 0.10.21
• 0.10.22
• 0.10.23
• 0.10.24
• 0.10.25
• 0.10.26
• 0.10.27
• 0.10.28
• 0.10.29
• 0.10.30
• 0.10.31
• 0.10.32
• 0.10.33
• 0.10.34
• 0.10.35
• 0.10.36
• 0.10.37
• 0.10.38
• 0.10.39
• 0.10.40
• 0.10.41
• 0.10.42
• 0.10.43
• 0.10.44
• 0.10.45
• 0.10.46
• 0.10.47
• 0.10.48
• 0.10.49
• 0.10.50
• 0.10.51
• 0.10.52
• 0.10.53
• 0.10.54
• 0.10.55
• 0.10.56
• 0.10.57
• 0.10.58
• 0.10.59
• 0.10.60
• 0.10.61
• 0.10.62
• 0.10.63
• 0.10.64
• 0.10.65
• 0.10.66
• 0.10.67
• 0.10.68
• 0.10.69
• 0.10.70
• 0.10.71
• 0.10.72
• 0.10.73
• 0.10.74
• 0.10.75
• 0.10.76
• 0.10.77
• 0.10.78

Support

• end of life (old version)

Website

• Product: https://github.com/rust-openssl/rust-openssl/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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