How severe is CVE-2020-12676?

CVE-2020-12676 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-12676 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-12676?

CVE-2020-12676 affects Fusionauth Samlv2. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-12676?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-12676 published?

CVE-2020-12676 was published on 2020-10-02 and last updated on 2026-06-17.

CVE-2020-12676

CVE-2020-12676 is a critical-severity vulnerability in Fusionauth Samlv2 with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.4
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Fusionauth Samlv2
Published: 2020-10-02
Last modified: 2026-06-17

Description

FusionAuth fusionauth-samlv2 0.2.3 allows remote attackers to forge messages and bypass authentication via a SAML assertion that lacks a Signature element, aka a "Signature exclusion attack".

Frequently asked questions

What is CVE-2020-12676?: FusionAuth fusionauth-samlv2 0.2.3 allows remote attackers to forge messages and bypass authentication via a SAML assertion that lacks a Signature element, aka a "Signature exclusion attack".
How severe is CVE-2020-12676?: CVE-2020-12676 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-12676 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-12676?: CVE-2020-12676 affects Fusionauth Samlv2. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-12676?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-12676 published?: CVE-2020-12676 was published on 2020-10-02 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:fusionauth:samlv2:0.2.3:*:*:*:*:*:*:*

Other CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities

CVE-2026-48558 — Critical (CVSS 10.0): SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the…
CVE-2023-25574 — Critical (CVSS 10.0): `jupyterhub-ltiauthenticator` is a JupyterHub authenticator for learning tools interoperability (LTI).…
CVE-2024-45409 — Critical (CVSS 10.0): The Ruby SAML library is for implementing the client side of a SAML authorization. Ruby-SAML in <= 12.2 and 1.13.0 <=…
CVE-2024-32962 — Critical (CVSS 10.0): xml-crypto is an xml digital signature and encryption library for Node.js. In affected versions the default…
CVE-2022-24884 — Critical (CVSS 10.0): ecdsautils is a tiny collection of programs used for ECDSA (keygen, sign, verify). `ecdsa_verify_[prepare_]legacy()`…
CVE-2021-33885 — Critical (CVSS 10.0): An Insufficient Verification of Data Authenticity vulnerability in B. Braun SpaceCom2 prior to 012U000062 allows a…

Browse all CWE-347 (Improper Verification of Cryptographic Signature) vulnerabilities →