---
title: "CVE-2026-49454: Relyra SAML SignatureValue not cryptographically verified -> authentication bypass"
url: https://erroneo.us/security/cve/CVE-2026-49454/
description: "CVE-2026-49454 (relyra (Hex (Erlang/Elixir))): Relyra is a strict-by-default SAML 2.0 Service Provider library for Elixir and Phoenix. Versions 1.0.0 and…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-18
date_modified: 2026-06-26
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-49454"
kev: false
cvss: 9.1
epss: 0.00226
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-49454: Relyra SAML SignatureValue not cryptographically verified -> authentication bypass

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.2% , percentile 13: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 13% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes relyra (Hex (Erlang/Elixir)) >= 1.0.0, < 1.2.0, fixed in 1.2.0 . Check your lockfile, including transitive dependencies.

## What it is

Relyra is a strict-by-default SAML 2.0 Service Provider library for Elixir and Phoenix. Versions 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. The XMLDSig trust boundary was incomplete as :publickey.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. A forged SignatureValue carrying an attacker-controlled NameID could be accepted as {:ok}. This issue has been fixed in version 1.2.0.

## Affected packages

- Hex (Erlang/Elixir) `relyra` >= 1.0.0, < 1.2.0 → fixed: 1.2.0

## Affected products (CVE record)

- szTheory relyra: >= 1.0.0, < 1.2.0

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.23% probability of exploitation activity in the next 30 days; percentile 13.

## Sources

- [GitHub Advisory GHSA-jv46-xfwm-36j7](https://github.com/advisories/GHSA-jv46-xfwm-36j7)
- [CVE.org record CVE-2026-49454](https://www.cve.org/CVERecord?id=CVE-2026-49454)
- [NVD entry CVE-2026-49454](https://nvd.nist.gov/vuln/detail/CVE-2026-49454)
- [github.com](https://github.com/szTheory/relyra/security/advisories/GHSA-jv46-xfwm-36j7)
- [github.com](https://github.com/szTheory/relyra/commit/2e456897af3158c175bb490ce7fc51d6241c8922)
- [github.com](https://github.com/szTheory/relyra/commit/8910200)

---
Source page: https://erroneo.us/security/cve/CVE-2026-49454/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt