# CVE-2026-12048: pgAdmin 4: Stored XSS via untrusted error and plan-node text rendered through html-react-parser

> Attacker-controlled PostgreSQL servers can inject malicious HTML into pgAdmin 4, enabling phishing or script execution within the application interface.

- **Severity:** Critical 9.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 18 Jun 2026
- **Updated:** 22 Jun 2026
- **Also known as:** GHSA-vmw6-74fq-69v8

## What is CVE-2026-12048?

CVE-2026-12048 is a critical cross-site scripting vulnerability in pgadmin.org pgAdmin 4, published on 18 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Stored cross-site scripting in pgAdmin 4's error-rendering and plan-node-rendering paths. Text returned by a PostgreSQL server (ErrorResponse messages, including object names quoted back inside relation-does-not-exist errors and inside EXPLAIN Recheck Cond / Exact Heap Blocks fields) was passed verbatim through html-react-parser at every user-facing sink — the notifier toasts, FormFooterMessage / FormInput help and error areas, FormNote, ModalProvider AlertContent and confirmDelete, ToolErrorView, the Explain visualiser's NodeText panel, the SQL editor confirm dialogs, ConfirmSaveContent, PreferencesHelper modal alerts, and SelectThemes helper text. A PostgreSQL server an attacker controls — or any server returning attacker-influenced text such as a table or column name a low-privilege database user can create — could inject arbitrary HTML (including <iframe>) into the pgAdmin DOM the moment the victim's pgAdmin connected to that server or viewed an Explain plan that referenced the crafted object.

The injected iframe's srcdoc could fetch attacker-served JavaScript and, by writing to parent.location, redirect the victim's top-level pgAdmin browser tab to an attacker-controlled URL. Because the injection originates from inside pgAdmin's own interface, standard anti-clickjacking controls (X-Frame-Options, Content-Security-Policy: frame-ancestors) do not mitigate it. A phishing page rendered inside the legitimate pgAdmin window is indistinguishable from a genuine pgAdmin dialog.

Fix combines three complementary layers. (1) DOMPurify sanitisation is wrapped around every html-react-parser call site reachable from notifier, alert, form-error, Explain, and SQL-editor flows. (2) A new plain-text rendering contract — SafeMessage / SafeHtmlMessage components plus Notifier.errorText / alertText / warningText / infoText / successText helpers — is introduced; around fifty callers across browser, tools, dashboard, debugger, misc, llm, preferences, schema diff, and the SQL editor that previously interpolated backend-derived strings are migrated to the plain-text variants. (3) Backend HTML-escape is applied at the post-connection-SQL handler (execute_post_connection_sql) via a new sanitize_external_text helper, so third-party JSON consumers (audit logs, API clients) never receive raw markup either; the Explain plan-info renderer is also patched to _.escape Recheck Cond and Exact Heap Blocks at construction (matching every sibling field), giving defence in depth even before DOMPurify runs.

This issue affects pgAdmin 4: from 6.0 before 9.16.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2026-12048?

It affects 1 product.


Products: Pgadmin Pgadmin 4.

## How do I fix CVE-2026-12048?

Apply the vendor's patch.

## Is CVE-2026-12048 being exploited?

There is no known exploitation of CVE-2026-12048 in the wild and no public exploit code.

## Other vulnerabilities in pgadmin.org pgAdmin 4

- [CVE-2025-2945](https://insights.sbomify.com/CVE-2025-2945/): pgAdmin 4: Remote Code Execution in Query Tool and Cloud Deployment (critical 9.9)
- [CVE-2024-9014](https://insights.sbomify.com/CVE-2024-9014/): OAuth2 client id and secret exposed through the web browser in pgAdmin 4 (critical 9.9)
- [CVE-2026-12046](https://insights.sbomify.com/CVE-2026-12046/): Deserialization in pgAdmin 4 (critical 9.5)
- [CVE-2026-17351](https://insights.sbomify.com/CVE-2026-17351/): SQL injection in pgAdmin 4 (critical 9.4)
- [CVE-2026-17566](https://insights.sbomify.com/CVE-2026-17566/): Command injection in pgAdmin 4 (critical 9.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12048 and fix it if it is affected.

What it is: CVE-2026-12048 is a critical cross-site scripting vulnerability in pgadmin.org pgAdmin 4, published on 18 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-12048 in the wild and no public exploit code.

Affected product: pgadmin.org pgAdmin 4. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-12048/ (Markdown: https://insights.sbomify.com/CVE-2026-12048/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12048
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12048
- OSV: https://osv.dev/vulnerability/CVE-2026-12048

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12048/
Summaries are generated and may contain mistakes; the official description above is the record.