Threats / Red Hat / CVE-2021-4034
CVE-2021-4034
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Red Hat Polkit vulnerability
Red Hat Polkit pkexec contains an out-of-bounds read/write vulnerability enabling privilege escalation to administrative rights.
Verdict
Today item — known-exploited.
A memory safety flaw in the pkexec utility allows unauthenticated local attackers to escalate privileges to root. The vulnerability has been actively exploited in the wild and carries high exploitation likelihood.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
43 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-06-27).
Probability (EPSS)
EPSS 0.94921 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Red Hat, Polkit. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-787 Out-of-bounds Write — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious command-line argument to trigger an out-of-bounds memory write in pkexec.
Business
An unprivileged user account on the system becomes compromised with root-level access.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute the exploit locally to gain administrative privileges without authentication.
Business
Attackers obtain full system control, enabling data theft, malware installation, and lateral movement.
3
Lateral reach — past segmentation narrative 3
Attacker
I use root access to establish persistence mechanisms and exfiltrate sensitive data.
Business
Confidentiality and integrity of the entire system are compromised; incident response and forensics become difficult.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05