# CVE-2026-21391: Improper Claim Validation in PingAM OIDC Provider

> Attackers can spoof ID Token claims to bypass authentication and escalate privileges in specific PingAM configurations.

- **Severity:** Critical 9.5 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/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:** 14 Sep 2026
- **Updated:** 14 Sep 2026
- **Also known as:** GHSA-cvq5-qf5h-v345

## What is CVE-2026-21391?

CVE-2026-21391 is a critical authentication bypass vulnerability in PingAM, published on 14 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An improper validation vulnerability exists within PingAM where a well-crafted request allows arbitrary or protected ID Token claims to be set or overridden. In certain configurations this could allow an attacker to bypass authentication controls via spoofing leading to privilege escalation or impersonation.

Weakness: CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2026-21391?


## How do I fix CVE-2026-21391?

No fix has been published for CVE-2026-21391 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-21391 being exploited?

There is no known exploitation of CVE-2026-21391 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-21391 and fix it if it is affected.

What it is: CVE-2026-21391 is a critical authentication bypass vulnerability in PingAM, published on 14 Sep 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-2026-21391 in the wild and no public exploit code.

Affected product: PingAM. 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-2026-21391/ (Markdown: https://insights.sbomify.com/CVE-2026-21391/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-21391
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-21391
- OSV: https://osv.dev/vulnerability/CVE-2026-21391

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-21391/
Summaries are generated and may contain mistakes; the official description above is the record.