# CVE-2026-49283: SimpleSAMLphp saml2 authentication bypass via TLS validator confusion

Source: https://junglewise.ai/threats/cve-2026-49283-simplesamlphp-saml2-authentication-bypass-via-tls-validator  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-02. Updated: 2026-07-02  
License: CC BY 4.0 with a link back

CVE-2026-49283 · Severity: high · CVSS 8.7 · Published 2026-07-02

SimpleSAMLphp is a widely used tool for managing digital identities and single sign-on (SSO). A security flaw in how it handles certain login requests allows a malicious or lower-trust identity provider to impersonate users from a different, more trusted provider. This could allow an attacker to gain unauthorized access to sensitive corporate systems by forging user identities.

Technologies: [simplesamlphp/saml2 (Packagist)](https://junglewise.ai/threats/technologies/simplesamlphp-saml2), [simplesamlphp/saml2-legacy (Packagist)](https://junglewise.ai/threats/technologies/simplesamlphp-saml2-legacy). Vendors: [Packagist](https://junglewise.ai/threats/vendors/packagist), [Simplesamlphp](https://junglewise.ai/threats/vendors/simplesamlphp).

## Quick answers

**Is CVE-2026-49283 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-49283 being exploited in the wild.

**How severe is CVE-2026-49283?** High severity, with a CVSS score of 8.7, published 2 July 2026.

**Which products and versions are affected?** simplesamlphp/saml2 (Packagist) ECOSYSTEM:introduced=6.0.0,fixed=6.2.1; simplesamlphp/saml2-legacy (Packagist) ECOSYSTEM:introduced=4.20.0,fixed=4.20.2; Simplesamlphp Saml2 >= 6.0.0, < 6.2.1; >= 5.0.0, < 5.0.6; < 4.20.2; Simplesamlphp Saml2-Legacy < 4.20.2.

**Is there a fix for CVE-2026-49283?** Yes. simplesamlphp/saml2 (Packagist): upgrade to 6.2.1 or later; simplesamlphp/saml2-legacy (Packagist): upgrade to 4.20.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-49283 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-49283?** Check whether you run simplesamlphp/saml2 (Packagist), simplesamlphp/saml2-legacy (Packagist), Simplesamlphp Saml2 or one of the others listed 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.

## How to fix

- simplesamlphp/saml2 (Packagist): upgrade to 6.2.1 or later

  ```sh
  composer require simplesamlphp/saml2:^6.2.1
  ```

- simplesamlphp/saml2-legacy (Packagist): upgrade to 4.20.2 or later

  ```sh
  composer require simplesamlphp/saml2-legacy:^4.20.2
  ```


## Technical details

A vulnerability exists in the HTTP-Artifact receive path of SimpleSAMLphp where TLS validator confusion occurs. In the `HTTPArtifact::receive()` flow, the `SOAPClient::validateSSL()` method fails to throw an exception when a TLS public key mismatch occurs, returning normally instead. Because `SAML2\Message::validate()` interprets any non-exception return as a successful validation, an unsigned SAML Response embedded in a SOAP ArtifactResponse from one IdP can be incorrectly validated against the metadata of a different IdP. This allows a malicious IdP to mint assertions for arbitrary users belonging to a higher-trust IdP within the same federation. The issue is patched in versions 6.2.1, 5.0.6, and 4.20.2.

## Affected products

- SimpleSAMLphp saml2 >= 6.0.0, < 6.2.1; >= 5.0.0, < 5.0.6; < 4.20.2
- SimpleSAMLphp saml2-legacy < 4.20.2

## Identifiers

- CVE-2026-49283
- GHSA-6929-8p9f-26jx

## Timeline

- 2026-05-29: disclosed
- 2026-07-02: advisory

## References

- [https://api.github.com/users/kamil-sawicki](https://api.github.com/users/kamil-sawicki)
- [https://github.com/kamil-sawicki](https://github.com/kamil-sawicki)
- [https://api.github.com/users/kamil-sawicki/gists%7B/gist_id%7D](https://api.github.com/users/kamil-sawicki/gists%7B/gist_id%7D)
- [https://api.github.com/users/kamil-sawicki/repos](https://api.github.com/users/kamil-sawicki/repos)
- [https://avatars.githubusercontent.com/u/38559302?v=4](https://avatars.githubusercontent.com/u/38559302?v=4)
- [https://api.github.com/users/kamil-sawicki/events%7B/privacy%7D](https://api.github.com/users/kamil-sawicki/events%7B/privacy%7D)

## Related threats

- [SimpleSAMLphp saml2 Denial of Service via XPath Transform](https://junglewise.ai/threats/cve-2026-49289-simplesamlphp-saml2-denial-of-service-via-xpath-transform)
- [The SimpleSAMLphp SAML2 library incorrectly verifies signatures for HTTP-Redirect binding](https://junglewise.ai/threats/cve-2025-27773-the-simplesamlphp-saml2-library-incorrectly-verifies-signatures)
- [SimpleSAMLphp SAML2 has an XXE in parsing SAML messages](https://junglewise.ai/threats/cve-2024-52806-simplesamlphp-saml2-has-an-xxe-in-parsing-saml-messages)
- [Validation of SignedInfo](https://junglewise.ai/threats/cve-2023-49087-validation-of-signedinfo)
- [SimpleSAMLphp SAML2 spoof SAML responses](https://junglewise.ai/threats/cve-2016-9814-simplesamlphp-saml2-spoof-saml-responses)