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CVE-2026-55891 none

Vulnerability in privatebin/privatebin (CVE-2026-55891)

Summary

Vulnerability in privatebin/privatebin (CVE-2026-55891). Risk of unauthorized operations or information disclosure. Exploitable via FILTER_SANITIZE_URL. Mitigation: upgrade to 2.0.5 or later.

Original description

The description as published by the source.

Vulnerability Details

A reflected JSON injection allows an attacker to return arbitrary data in the JSON endpoints (like /?jsonld= and /?pasteid).

Root Cause

Request::getRequestUri() sanitizes $_SERVER['REQUEST_URI'] with FILTER_SANITIZE_URL:

public function getRequestUri()
{
    $uri = array_key_exists('REQUEST_URI', $_SERVER) ? filter_var($_SERVER['REQUEST_URI'], FILTER_SANITIZE_URL) : '';
    return empty($uri) ? '/' : $uri;
}

FILTER_SANITIZE_URL does not strip ", ', <, > characters (per the PHP manual's allowed-character list for this filter). So the raw, attacker-controlled request URI (including query string) passes through almost unmodified into Controller::$_urlBase (set in _init()).

In Controller::_jsonld(), $_urlBase is spliced directly into one of the static .jsonld templates (js/types.jsonld, js/paste.jsonld, etc.) with a plain str_replace(), without any JSON-escaping:

$content = str_replace(
    '?jsonld=',
    $this->_urlBase . '?jsonld=',
    file_get_contents($file)
);
...
header('Content-type: application/ld+json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: GET');
echo $content;

A request URI containing a literal " therefore breaks out of the JSON string in the "@context"."pb" value and injects arbitrary attacker-controlled key/value pairs into the response body, which is served with Content-Type: application/ld+json and `Access-Control-Al…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-55891 has been found in privatebin/privatebin.
Attackers can target a specific entry point like FILTER_SANITIZE_URL over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade privatebin/privatebin to 2.0.5 or later.
If unsure, ask your IT team or search "privatebin/privatebin CVE-2026-55891" on the vendor's site.

CVE-2026-55891 (privatebin/privatebin) — CWE-116
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: FILTER_SANITIZE_URL / jsonld
Patched: 2.0.5 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-116) exists in privatebin/privatebin. Attackers reach the vulnerable code path via FILTER_SANITIZE_URL without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of privatebin/privatebin. Attack surface: FILTER_SANITIZE_URL / jsonld.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 2.0.5.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'privatebin/privatebin' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'privatebin/privatebin' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で privatebin/privatebin を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade privatebin/privatebin to 2.0.5

    ステージング環境で 2.0.5 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

composer privatebin/privatebin
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.5"}]}]
Packagist privatebin/privatebin
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.5"}]}]

References

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