CVE-2021-22600: Linux Kernel Privilege Escalation Vulnerability
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Linux Kernel contains a flaw in the packet socket (AF_PACKET) implementation which could lead to incorrectly freeing memory. A local user could exploit this for denial-of-service (DoS) or possibly for privilege escalation.
CSIRTS triage
- What
- The vulnerability in the packet socket implementation could lead to incorrectly freeing memory.
- Who is affected
- Local users of the Linux Kernel are affected.
- Urgency
- Remediation is urgent due to the potential for privilege escalation and denial-of-service exploitation.
- Action
- Apply the latest patches for the Linux Kernel.
AI-assisted analysis generated from the source advisory — verify against the original.
⚡ Watch Linux Kernel
Get an email when a new Linux Kernel advisory drops — max one per day, one-click unsubscribe.
Details
Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-22600
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Exploitation confirmedCVE-2021-22600Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 92% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2021-22600 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Linux Kernel Privilege
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- medium[UPDATE] [medium] Linux Kernel: Vulnerability allows privilege escalationcert-bund · 2026-07-10
- high[UPDATE] [high] Linux Kernel: Vulnerability allows privilege escalationcert-bund · 2026-07-10
- high[UPDATE] [high] Linux Kernel: Vulnerability allows privilege escalationcert-bund · 2026-07-10
- medium[UPDATE] [medium] Linux Kernel: Vulnerability allows privilege escalation and denial of servicecert-bund · 2026-07-07
- high[UPDATE] [high] Linux Kernel: Multiple vulnerabilities allow denial of service and privilege escalationcert-bund · 2026-07-06
- unknownFragnesia Local Privilege Escalation report via ESP-in-TCP in the Linux Kernelaws · 2026-06-05
More from CISA Known Exploited Vulnerabilities
- criticalCVE-2026-48939: iCagenda Unrestricted Upload of File with Dangerous Type Vulnerability2026-07-10
- criticalCVE-2026-56291: Balbooa Forms Unrestricted Upload of File with Dangerous Type Vulnerability2026-07-10
- criticalCVE-2026-48908: JoomShaper SP Page Builder Unrestricted Upload of File with Dangerous Type Vulnerability2026-07-07
- criticalCVE-2026-55255: Langflow Authorization Bypass Through User-Controlled Key Vulnerability2026-07-07
- criticalCVE-2026-48282: Adobe ColdFusion Path Traversal Vulnerability2026-07-07