CVE-2021-21551 — Dell dbutil Driver Insufficient Access Control Vulnerability
Dell dbutil_2_3.sys driver contains an insufficient access control vulnerability which may lead to escalation of privileges, denial of service, or information disclosure. Local authenticated user access is required.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Confirmed exploitation (CISA KEV)+35
- Public exploit/PoC (metasploit, exploitdb, github)+20
- EPSS 79.2% (30-day exploitation probability)+15
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented mitigation — www.dell.com (NIST National Vulnerability Database)
CISA required action CISA
Apply updates per vendor instructions.
US federal deadline: Apr 21, 2022 — passed 1639 day(s) ago
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Dell Dbutil).
- Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
- Apply the documented mitigations until a definitive fix is available.
- EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 8.8 | CVSS 3.1 | High | 2.0 | 6.0 | security_alert@emc.com via NIST National Vulnerability Database |
| 8.8 | CVSS 3.1 | High | — | — | dell via CVE Program (cve.org) e CISA ADP |
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | nvd@nist.gov via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | GitHub, Inc. via GitHub Security Advisories |
| 4.6 | CVSS 2.0 | Medium | 3.9 | 6.4 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CISA KEV details CISA
CISA lists a CVE once it has evidence of exploitation against real targets.
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.
Public exploits, PoCs and detection templates
Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.
- Dell DBUtil_2_3.sys IOCTL memmove good May 4, 2021
- Exploit to SYSTEM for CVE-2021-21551 ★ 258 May 13, 2021
- Cobalt Strike (CS) Beacon Object File (BOF) foundation for kernel exploitation using CVE-2021-21551. ★ 85 Jun 25, 2022
- arbitrary kernel read/write in dbutil_2_3.sys, Proof of Concept Local Privilege Escalation to nt authority/system ★ 60 May 30, 2021
- Dell Driver EoP (CVE-2021-21551) ★ 32 Sep 3, 2021
- Dell Driver EoP (CVE-2021-21551) ★ 26 Jan 7, 2023
- ch3rn0byl/CVE-2021-21551 ★ 24 May 21, 2021
- An extended proof-of-concept for the CVE-2021-21551 Dell ‘dbutil_2_3.sys’ Kernel Exploit ★ 23 Jun 2, 2021
- Proof of concept exploit for CVE-2021-21551 ★ 2 Aug 2, 2024
- Script to patch your domain computers about the CVE-2021-21551. Privesc on machines that have the driver dbutil_2_3.sys, installed by some DELL tools (BIOS updater, SupportAssist...) ★ 1 May 28, 2021
- Exploit implementation for CVE-2021-21551 ★ 0 Jan 11, 2025
Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 79.25%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
- Hunt retroactively in logs from before Mar 31, 2022 (KEV listing): exploitation may have started earlier.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · dell/dbutil
- SSVC assessment updated
- Record published
- Fix documented
- Affected products added · dell/dbutil
- CVSS changed · 7.8
- Source status changed · → Analyzed
- Added to CISA KEV (detected)
- Record created in this database
- 2022
- Added to CISA KEV catalog
- 2021
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 13, 2026 – Oct 13, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
6 on the record
- www.dell.com/support/kbdoc/en-us/000186019/dsa-2021-088-dell-client-platform-secur
- www.cisa.gov/known-exploited-vulnerabilities-catalog
- packetstormsecurity.com/files/162604/Dell-DBUtil_2_3.sys-IOCTL-Memory-Read-Write.html
- github.com/advisories/GHSA-pp2j-9hqv-7x55
- nvd.nist.gov/vuln/detail/CVE-2021-21551
- packetstormsecurity.com/files/162739/DELL-dbutil_2_3.sys-2.3-Arbitrary-Write-Privilege-Escala
Elsewhere on this site
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2021-21551 is "Dell dbutil Driver Insufficient Access Control Vulnerability", rated High. It affects Dbutil (Dell); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.8 describes technical severity. EPSS 79.25% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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