No exploitation reportedFix available

CVE-2021-28847

Q: Is CVE-2021-28847 actively exploited?

Active exploitation of CVE-2021-28847 has not been confirmed. Its EPSS score was 1.4% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-28847?

CVE-2021-28847 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.

No exploitation reported by the sources we read.

Published2021-06-03
Fixed in21.0

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

MobaXterm before 21.0 allows remote servers to cause a denial of service (Windows GUI hang) via tab title change requests that are sent repeatedly at high speed, which results in many SetWindowTextA or SetWindowTextW calls.

Timeline

dates in UTC

2021-06-0311:15CVE 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-2021-28847?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-28847?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Mobatek mobaxterm

Branch	Affected	Fixed in	Source
21.0	< 21.0	21.0	NVD

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

Fix

Update Mobatek mobaxterm to 21.0

Advisories and patches

mobaxterm.mobatek.netRelease Notes · Vendor Advisory
mobaxterm.mobatek.netRelease Notes · Vendor 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 2.05read 2026-10-23
FIRST EPSSEPSS score1.4 %2026-10-23

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: 2021-06-03
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-28847?

Is CVE-2021-28847 actively exploited?

Active exploitation of CVE-2021-28847 has not been confirmed. Its EPSS score was 1.4% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-28847?

CVE-2021-28847 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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