CVE-2021-22600: Linux Kernel Privilege Escalation Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 75 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 6.6%
EPSS score, percentile 93.8 of all scored records
- How severe?
- 6.6 Medium
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA deadline . Apply updates per vendor instructions.
- Which versions are affected?
Affected
- before 5.4.168
- before 5.10.88
- before 5.15.11
- before 5.16-rc6
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | before 5.4.168 |
| Affected | before 5.10.88 |
| Affected | before 5.15.11 |
| Affected | before 5.16-rc6 |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2021-22600 to its Known Exploited Vulnerabilities (KEV) catalog on 11 Apr 2022.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 2 May 2022.
- The CVE record was published on 26 Jan 2022, 75 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 6.6 (Medium), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 6.6% (percentile 93.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact partial.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
Double Free in net/packet/af_packet.c leading to priviledge escalation
A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
- CWE-415: Double Free
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
- git.kernel.org
- [debian-lts-announce] 20220309 [SECURITY] [DLA 2941-1] linux-4.19 security update
- security.netapp.com
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