# CVE-2026-123798: SuperTokens Core: SAML XML Signature Wrapping authentication bypass — any IdP user can authenticate as any other user


- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 9 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-gvx2-mwmj-wwvj

## What is CVE-2026-123798?

CVE-2026-123798 is a high-severity vulnerability in supertokens-core, published on 9 Nov 2026. 

### Official description

SuperTokens Core is an open source authentication server. From 11.3.0 until 11.3.7, 11.4.7, and 12.0.10, SAML.verifySamlResponseSignature calls OpenSAML SignatureValidator.validate without first applying SAMLSignatureProfileValidator. The Core can therefore accept a cryptographically valid signature that references a different XML element from the Response or Assertion whose NameID and attributes are used for authentication. An ordinary user of the configured identity provider can move a genuinely signed element elsewhere in the document while supplying an attacker-authored identity-bearing element, causing XML Signature Wrapping authentication as another IdP user. Both response-level and assertion-level signing paths are affected, and SP-initiated login remains reachable without enabling allowIDPInitiatedLogin. This issue is fixed in versions 11.3.7, 11.4.7, and 12.0.10.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature), CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2026-123798?


## How do I fix CVE-2026-123798?

No fix has been published for CVE-2026-123798 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123798 being exploited?

There is no known exploitation of CVE-2026-123798 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123798 and fix it if it is affected.

What it is: CVE-2026-123798 is a high-severity vulnerability in supertokens-core, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123798 in the wild and no public exploit code.

Affected product: supertokens-core. 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-2026-123798/ (Markdown: https://insights.sbomify.com/CVE-2026-123798/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123798
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123798
- OSV: https://osv.dev/vulnerability/CVE-2026-123798

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123798/
Summaries are generated and may contain mistakes; the official description above is the record.