Threats / Linux / CVE-2021-22600
CVE-2021-22600
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Linux Kernel vulnerability
Linux Kernel packet socket implementation contains a use-after-free flaw allowing local users to trigger denial-of-service or potentially escalate privileges.
Verdict
Today item — known-exploited.
A use-after-free vulnerability in AF_PACKET socket handling enables local attackers to crash the kernel or gain elevated privileges. Exploitation requires local system access and has been observed in active attacks.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
4 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 2022-04-11).
Probability (EPSS)
EPSS 0.05918 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Linux, Kernel. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-415 Double Free — 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 packet socket operation to trigger incorrect memory deallocation.
Business
System availability is compromised through kernel crash or unexpected termination of critical processes.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I exploit the memory corruption to read or write kernel memory, escalating my privileges to root.
Business
Attacker gains administrative control, enabling data theft, malware installation, or lateral movement across the infrastructure.
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