CVE & CISA-KEV Catalog

CVE-2026-55891

UNSCORED

Description

PrivateBin is an online pastebin where the server has zero knowledge of pasted data. Prior to 2.0.5, Request::getRequestUri() in lib/Request.php passes $_SERVER['REQUEST_URI'] through FILTER_SANITIZE_URL, which does not remove quotation marks, angle brackets, or apostrophes, and Controller::_init() stores the attacker-controlled value in Controller::$_urlBase. Controller::_jsonld() in lib/Controller.php then uses str_replace() to insert that value without JSON escaping into js/types.jsonld, js/paste.jsonld, and the other JSON-LD templates used by /?jsonld= and /?pasteid. A raw quotation mark delivered by an HTTP client, proxy, or structured-data crawler that does not normalize the request target can break out of the JSON string and inject arbitrary key-value data into a CORS-open application/ld+json response. The jsonld branch in Controller::__construct() returns before _setCacheHeaders(), so the response also lacks X-Content-Type-Options: nosniff, Content Security Policy, X-Frame-Options, and Referrer-Policy. Direct script execution was not demonstrated, but manipulated responses can affect structured-data consumers or combine with less strict clients. This issue is fixed in version 2.0.5.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.33%probability of exploitation in 30 days
25thpercentile

Low risk: more likely to be exploited than 25% of all known CVEs.

References

Related Vulnerabilities

Other CWE-116 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-38475Critical9.1100%KEVFix
CVE-2022-36446Critical9.896%-Fix
CVE-2021-31806Medium6.596%-Fix
CVE-2022-30781High7.589%-Fix
CVE-2022-36099Critical9.976%-Fix
CVE-2022-36100Critical9.974%-Fix

Common questions

How do I fix CVE-2026-55891?

No published fix for CVE-2026-55891 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

Is CVE-2026-55891 being actively exploited?

Not that we know of. CVE-2026-55891 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.33% is the estimated probability that it will be exploited in the next 30 days. That is higher than 25% of all scored CVEs.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-28.