What is CVE-2021-42278?
Active Directory Domain Services Elevation of Privilege Vulnerability
The record classifies CVE-2021-42278 under weakness class NVD-CWE-noinfo. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 9 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 1813 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.5 — HIGH
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - EPSS (FIRST)
- 73.2% probability of exploitation in the next 30 days, higher than 99.4% of all scored CVEs
- CISA KEV
- Listed since 2022-04-11, federal remediation deadline 2022-05-02 — used in known ransomware campaigns
- Threadlinqs priority
- 10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum
- Published
- 2021-11-10, last modified 2026-08-19
Is CVE-2021-42278 being exploited?
CISA added CVE-2021-42278 to the Known Exploited Vulnerabilities catalog on 2022-04-11, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2022-05-02 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. Weaponised exploit code for CVE-2021-42278 is publicly available. 7 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 58 in the Threadlinqs vulnerability feed.
- safebuffer/sam-the-admin (github)
- Ridter/noPac (github)
- ly4k/Pachine (github)
- waterrr/noPac (github)
- cybersecurityworks553/noPac-detection (github)
- xLTJ/noPac (github)
- trickest/cve (trickest)
Affected products and versions
- Microsoft: Windows Server 2004, Windows Server 2008, Windows Server 2008 r2, Windows Server 2012, Windows Server 2012 r2, Windows Server 2016, Windows Server 2019, Windows Server 2022, Windows Server 20h2
How to fix CVE-2021-42278
The record marks a vendor fix as available for CVE-2021-42278. Patch reference: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278. Vendor advisory: https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42278. Because CVE-2021-42278 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2022-05-02. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2021-42278
5 tracked threats in the Threadlinqs corpus reference CVE-2021-42278, either in the campaign’s CVE list or as an indicator on the campaign record.
- k0t (CryptoFeel / Scrooge) Network-Edge Intrusion Campaign Targeting FortiGate, FortiWeb and GlobalProtect (CVE-2025-64446, CVE-2026-0257) — HIGH · 2026-10-21
- Abliterated and Resold AI Models Fueling Cybercrime Underground; ARTEX-Assisted Intrusions at South Korean Banks (Flare Quantitative Analysis) — HIGH · 2026-10-20
- PaperCut NG/MF Chained Zero-Day RCE (CVE-2026-82078 & CVE-2026-81578) Under Active Exploitation — CRITICAL · 2026-08-28
- Capita Black Basta Ransomware Incident (March 2023) — Record £14M UK ICO Fine for 6M+ Affected Individuals — HIGH · 2026-06-10
- Black Basta Ransomware: Internal Chat Leaks Expose $100M+ RaaS Operation — Conti Successor Unmasked — HIGH · 2026-02-12
Sources
Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.