# CVE-2026-19503: Insufficient OIDC endpoint validation could invoke unintended local protocol handlers

> Attackers can trigger local protocol handlers via malicious OIDC endpoints, potentially exposing credentials or executing code in the user's context.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Aug 2026
- **Updated:** 13 Aug 2026
- **Also known as:** GHSA-gxxm-9rmv-h4mp, UBUNTU-CVE-2026-19503

## What is CVE-2026-19503?

CVE-2026-19503 is a medium-severity server-side request forgery vulnerability in MongoDB Atlas SQL ODBC Driver, published on 12 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

MongoDB Schema Manager and MongoDB Atlas SQL ODBC Driver do not validate the scheme of the authorization and token endpoints returned by an OIDC issuer's discovery document. A user induced to connect to an uncontrolled MongoDB deployment using MONGODB-OIDC authentication may have an uncontrolled URI dispatched to their operating system's default protocol handler, potentially exposing credentials or, under certain conditions, resulting in code execution in the user's context.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2026-19503?

It affects 2 products.


Products: Mongodb Odbc Driver, Mongodb Sql Schema Builder Cli.

## How do I fix CVE-2026-19503?

No fix has been published for CVE-2026-19503 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-19503 being exploited?

There is no known exploitation of CVE-2026-19503 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-19503 and fix it if it is affected.

What it is: CVE-2026-19503 is a medium-severity server-side request forgery vulnerability in MongoDB Atlas SQL ODBC Driver, published on 12 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-19503 in the wild and no public exploit code.

Affected product: MongoDB Atlas SQL ODBC Driver. 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-2026-19503/ (Markdown: https://insights.sbomify.com/CVE-2026-19503/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-19503
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-19503
- OSV: https://osv.dev/vulnerability/CVE-2026-19503

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-19503/
Summaries are generated and may contain mistakes; the official description above is the record.