No exploitation reportedFix available

CVE-2020-27847

Q: Is CVE-2020-27847 actively exploited?

Active exploitation of CVE-2020-27847 has not been confirmed. Its EPSS score was 1.7% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2020-27847?

CVE-2020-27847 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2021-05-28
Fixed in2.27.0
WeaknessCWE-228

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability exists in the SAML connector of the github.com/dexidp/dex library used to process SAML Signature Validation. This flaw allows an attacker to bypass SAML authentication. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. This flaw affects dex versions before 2.27.0.

Timeline

dates in UTC

2021-05-2811:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-27847?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-27847?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Linuxfoundation dex

Branch	Affected	Fixed in	Source
2.27	< 2.27.0	2.27.0	NVD · OSV

russellhaering/goxmldsig

Branch	Affected	Fixed in	Source
1.1	< 1.1.0	1.1.0	OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Linuxfoundation dex to 2.27.0

Advisories and patches

github.comPatch
mattermost.comVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
CNAweakness (CWE)CWE-228read 2026-10-23
FIRST EPSSEPSS score1.7 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-05-28
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-27847?

Is CVE-2020-27847 actively exploited?

Active exploitation of CVE-2020-27847 has not been confirmed. Its EPSS score was 1.7% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-27847?

CVE-2020-27847 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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