{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-52778: YesWiki has Unsafe eval() in Formula Calculator - Remote Code Execution (RCE) & Denial of Service (DoS)","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-52778","status":"final","version":"1","initial_release_date":"2026-06-08T18:24:21.671Z","current_release_date":"2026-06-09T15:56:22.423Z","revision_history":[{"date":"2026-06-08T18:24:21.671Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-52778 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-52778"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-52778"},{"category":"external","summary":"https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8","url":"https://github.com/YesWiki/yeswiki/security/advisories/GHSA-px5m-h76g-p7p8"},{"category":"external","summary":"https://github.com/YesWiki/yeswiki/commit/dd2bd8fb099de0d21504bda8a810693b3fcb8e52","url":"https://github.com/YesWiki/yeswiki/commit/dd2bd8fb099de0d21504bda8a810693b3fcb8e52"},{"category":"external","summary":"https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6","url":"https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6"}]},"product_tree":{"branches":[{"category":"vendor","name":"YesWiki","branches":[{"category":"product_name","name":"yeswiki","branches":[{"category":"product_version","name":"< 4.6.6","product":{"name":"YesWiki yeswiki < 4.6.6","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:yeswiki:yeswiki:\\<_4.6.6:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-52778","title":"YesWiki has Unsafe eval() in Formula Calculator - Remote Code Execution (RCE) & Denial of Service (DoS)","notes":[{"category":"description","text":"YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex recursive regular expression before passing them to the PHP eval() function. This implementation is inherently flawed: it is vulnerable to Regular Expression Denial of Service (ReDoS / Stack Overflow) which can crash the server, and it creates a high-risk architecture where any logic bypass directly results in arbitrary PHP code execution. Version 4.6.6 patches the issue.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}