YesWiki up to 4.6.5 Signature Verification verifySignature return value

Summaryinfo

A vulnerability, which was classified as critical, has been found in YesWiki up to 4.6.5. The impacted element is the function HttpSignatureService::verifySignature of the component Signature Verification. The manipulation leads to return value. This vulnerability is uniquely identified as CVE-2026-52767. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, has been found in YesWiki up to 4.6.5. This issue affects the function HttpSignatureService::verifySignature of the component Signature Verification. The manipulation with an unknown input leads to a return value vulnerability. Using CWE to declare the problem leads to CWE-252. The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions. Impacted is integrity, and availability. The summary by CVE is:

YesWiki is a wiki system written in PHP. From version 4.6.2 to before version 4.6.6, HttpSignatureService::verifySignature() checks the result of PHP's openssl_verify() with a loose boolean negation - if (!openssl_verify(...)) { throw ... }. PHP's openssl_verify has four possible return values: 1, 0, -1, and "false". The -1 row is the bypass: PHP's truthiness rules make -1 a truthy value, so !(-1) === false, the throw is skipped, and the controller proceeds to processActivity(). Any condition that makes OpenSSL's EVP_VerifyFinal() return -1 triggers the bypass. The reachable consequence is the controller silently treats a failed verification as success and processes the attacker's payload. This issue has been patched in version 4.6.6.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-52767 since 06/08/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

Upgrading to version 4.6.6 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Type

• Content Management System

Name

• YesWiki

Version

• 4.6.0
• 4.6.1
• 4.6.2
• 4.6.3
• 4.6.4
• 4.6.5

Website

• Product: https://github.com/YesWiki/yeswiki/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion