# github.com/crewjam/saml nil-pointer panic and namespace-blind NameID

Source: https://junglewise.ai/threats/go-2026-6909-nil-pointer-panic-in-validateassertion-and-namespace-blind-ee835aff  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-05. Updated: 2026-11-07  
License: CC BY 4.0 with a link back

Severity: info · Published 2026-11-05

The crewjam/saml library, used in Go applications for SAML authentication, contains two defects in how it processes SAML assertions from identity providers. First, a missing validation check can crash the application if an assertion lacks an Issuer element. Second, the library accepts identity spoofing through a foreign XML namespace element, allowing an attacker with a valid signature from the trusted identity provider to impersonate other users.

Technologies: [github.com/crewjam/saml (Go)](https://junglewise.ai/threats/technologies/github-com-crewjam-saml). Vendors: [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** Informational severity, published 5 November 2026.

**Which products and versions are affected?** Crewjam Saml all versions through v0.5.1; github.com/crewjam/saml (Go) SEMVER:introduced=0.

**Is there a fix for This vulnerability?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run Crewjam Saml or github.com/crewjam/saml (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The library dereferences assertion.Issuer without nil-checking when ExpectedIDPEntityID is non-empty, causing a nil-pointer panic if a signed assertion omits the saml:Issuer element. Additionally, Subject.NameID uses a bare xml:"NameID" tag that matches NameID elements in any namespace, permitting encoding/xml to populate the field from foreign-namespace elements within saml:Subject, enabling an authenticated principal to spoof Subject.NameID.Value. Both issues affect all versions through v0.5.1 with no published fix available.

## Affected products

- crewjam saml all versions through v0.5.1

## Timeline

- 2026-11-05: disclosed: Public disclosure via Go vulnerability database

## References

- [https://github.com/golang/vulndb/issues/6909](https://github.com/golang/vulndb/issues/6909)
- [https://pkg.go.dev/vuln/GO-2026-6909](https://pkg.go.dev/vuln/GO-2026-6909)

## Related threats

- [GO-2023-2114 - Cross-site scripting via missing binding syntax validation in github.com/crewjam/saml](https://junglewise.ai/threats/cve-2023-45683-cross-site-scripting-via-missing-binding-syntax-validation)
- [GO-2023-1664 - Denial of service via deflate compression bomb in github.com/crewjam/saml](https://junglewise.ai/threats/cve-2023-28119-crewjam-saml-vulnerable-to-denial-of-service-via-deflate)
- [GO-2022-1129 - Authentication bypass in github.com/crewjam/saml](https://junglewise.ai/threats/cve-2022-41912-crewjam-saml-vulnerable-to-signature-bypass-via-multiple)
- [GO-2021-0058 - Signature validation bypass due to XML processing error in github.com/crewjam/saml](https://junglewise.ai/threats/cve-2020-27846-xml-processing-error-in-github-com-crewjam-saml)