CVE-2026-55891

UNRATEDCVSS · not yet scoredElevated
—
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • No CVSS published and no exploitation signals yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS v2: —Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
—
EchelonGraph score
Not yet assessedNo source has published severity data for this CVE yet — no CVSS score from NVD or a CNA, no GitHub advisory, and it is not in CISA KEV. This is not a rating of zero; we cannot assess it yet.
EG Score
—
EG Risk
—
EPSS PROB
0%
EPSS %ILE
26%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 9, 2026

References (4)

Vendor Advisories for CVE-2026-55891(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
privatebin/privatebin1.0 ... 2.0.4 (35 versions)2.0.5—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 22× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 19:28 UTCEPSS rescore
  2. 2026-09-17 19:31 UTCEPSS rescore
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 05:15 UTCEPSS rescore
  5. 2026-09-15 03:11 UTCEPSS rescore
  6. 2026-09-13 16:47 UTCEPSS rescore
  7. 2026-09-11 14:53 UTCEPSS rescore
  8. 2026-09-10 09:35 UTCEPSS rescore
  9. 2026-09-08 22:01 UTCEPSS rescore
  10. 2026-09-07 16:01 UTCEPSS rescore
  11. 2026-09-06 13:47 UTCEPSS rescore
  12. 2026-09-04 05:07 UTCEPSS rescore
  13. 2026-09-02 14:12 UTCEPSS rescore
  14. 2026-09-01 13:54 UTCEPSS rescore
  15. 2026-09-01 04:40 UTCEPSS rescore
  16. 2026-08-31 19:20 UTCNVD update
  17. 2026-08-31 18:56 UTCEG score recompute
  18. 2026-08-31 18:49 UTCMITRE cvelistV5
  19. 2026-08-30 19:17 UTCEPSS rescore
  20. 2026-08-30 01:22 UTCEPSS rescore
  21. 2026-08-28 22:34 UTCNVD update
  22. 2026-08-28 21:11 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-55891?
CVE-2026-55891 is a publicly disclosed vulnerability published on August 28, 2026. 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['REQUESTURI'] through FILTERSANITIZEURL, which does not remove quotation marks, angle brackets, or apostrophes, and Controller::init()…
When was CVE-2026-55891 disclosed?
CVE-2026-55891 was first published in the National Vulnerability Database on August 28, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55891 actively exploited?
CVE-2026-55891 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 73.9% of all scored CVEs.
How do I remediate CVE-2026-55891?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55891, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-55891

Explore →

Is Your Infrastructure Affected by CVE-2026-55891?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs