How severe is CVE-2020-26290?

CVE-2020-26290 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2020-26290 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-26290?

CVE-2020-26290 affects Linuxfoundation Dex. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-26290?

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-2020-26290 published?

CVE-2020-26290 was published on 2020-12-28 and last updated on 2026-06-17.

CVE-2020-26290

CVE-2020-26290 is a critical-severity vulnerability in Linuxfoundation Dex with a CVSS 3.x base score of 9.3. 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 9.3)
CVSS v2: 6.8
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Linuxfoundation Dex
Published: 2020-12-28
Last modified: 2026-06-17

Description

Dex is a federated OpenID Connect provider written in Go. In Dex before version 2.27.0 there is a critical set of vulnerabilities which impacts users leveraging the SAML connector. The vulnerabilities enables potential signature bypass due to issues with XML encoding in the underlying Go library. The vulnerabilities have been addressed in version 2.27.0 by using the xml-roundtrip-validator from Mattermost (see related references).

Frequently asked questions

What is CVE-2020-26290?: Dex is a federated OpenID Connect provider written in Go. In Dex before version 2.27.0 there is a critical set of vulnerabilities which impacts users leveraging the SAML connector. The vulnerabilities enables potential signature bypass due to issues with XML encoding in the underlying Go library. The vulnerabilities have been addressed in version 2.27.0 by using the xml-roundtrip-validator from Mattermost (see related references).
How severe is CVE-2020-26290?: CVE-2020-26290 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2020-26290 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-26290?: CVE-2020-26290 affects Linuxfoundation Dex. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-26290?: 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-2020-26290 published?: CVE-2020-26290 was published on 2020-12-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:linuxfoundation:dex:*:*:*:*:*:*:*:*

More vulnerabilities in Linuxfoundation Dex

CVE-2020-27847 — Critical (CVSS 9.8): A vulnerability exists in the SAML connector of the github.com/dexidp/dex library used to process SAML Signature…
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CVE-2024-23656 — High (CVSS 7.5): Dex is an identity service that uses OpenID Connect to drive authentication for other apps. Dex 2.37.0 serves HTTPS…

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