CVE-2026-49454 is a critical-severity (CVSS 9.1) Improper Authentication vulnerability in relyra. A fix is available for relyra — see the affected versions and patch details below.
Relyra SAML SignatureValue not cryptographically verified -> authentication bypass
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-49454.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-49454 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
relyraReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Relyra 1.0.0 and 1.1.0 accept forged SAML signatures because SignatureValue was not cryptographically verified before the library returned a successful authentication result.
Details
In 1.0.0 and 1.1.0, the XMLDSig trust boundary was incomplete. :public_key.verify over the exclusive-C14N canonicalized SignedInfo was not performed against the configured IdP certificate's public key, DigestValue was not recomputed over the canonicalized referenced element, and canonicalize/2 remained an unused passthrough in the signature-verification path. The result was a structure-only acceptance path where document shape and trust-source rejection could succeed without proving the signature bytes.
Impact
A forged SignatureValue carrying an attacker-controlled NameID can be accepted as {:ok}. Any relying-party application using Relyra 1.0.0 or 1.1.0 can be logged into as an arbitrary user if it trusts the affected response path.
Patches
Relyra 1.2.0 closes the gap with real exclusive-C14N canonicalization, :public_key.verify against the configured IdP certificate's public key, and a constant-time DigestValue recompute/compare bound to the exact consumed node on both verify/4 and verify_metadata_root/4.
Workarounds
There is no safe configuration of 1.0.0 or 1.1.0. Upgrade to 1.2.0 or later.
Resources
- Fix commit
2e45689(wire real XMLDSig crypto into the candidate arm) - Fix commit
8910200(close metadata trust bypass, pin over DER) - Regression proof:
test/security/xml/adversarial_crypto_test.exs,test/relyra/metadata/auto_refresh_test.exs,test/security/ci_gate_integrity_test.exs
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | relyra | ≥ 1.0.0&&< 1.2.0 | 1.2.0mix deps.update relyra |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for relyra, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update relyra to 1.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-49454 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-49454 in your dependencies?
Find it across Hex, including transitive dependencies.