No exploitation reported

CVE-2020-27782

No exploitation reported by the sources we read.

Published2021-02-23
WeaknessCWE-400

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 flaw was found in the Undertow AJP connector. Malicious requests and abrupt connection closes could be triggered by an attacker using query strings with non-RFC compliant characters resulting in a denial of service. The highest threat from this vulnerability is to system availability. This affects Undertow 2.1.5.SP1, 2.0.33.SP2, and 2.2.3.SP1.

Timeline

dates in UTC

2021-02-2319:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 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-2020-27782?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-27782?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Redhat undertow

Branch	Affected	Fixed in	Source
2.0	= 2.0.33	no fix published	NVD
2.1	= 2.1.5	no fix published	NVD
2.2	= 2.2.3	no fix published	NVD

Redhat jboss fuse

Branch	Affected	Fixed in	Source
6.0	= 6.0.0	no fix published	NVD
7.0	= 7.0.0	no fix published	NVD

Redhat openshift application runtimes

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

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

Fix

Advisories and patches

bugzilla.redhat.comVendor Advisory

Detection

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

Sources

NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.07.8read 2026-10-23
CNAweakness (CWE)CWE-400read 2026-10-23
FIRST EPSSEPSS score1.4 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2021-02-23
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2020-27782?

Is CVE-2020-27782 actively exploited?

Active exploitation of CVE-2020-27782 has not been confirmed. Its EPSS score was 1.4% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-27782?

CVE-2020-27782 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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