November 13, 2026 Follow Egret
CVE-2021-22600 · CVE record: PUBLISHED

Double Free in net/packet/af_packet.c leading to priviledge escalation

Linux Kernel Kernel

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

Exploitation evidence

Known exploited · CISA KEV listed

Added 2022-04-11. Ransomware campaign use: Unknown.

CISA required action: Apply updates per vendor instructions.

CISA due date: 2022-05-02. This is the catalog’s deadline, not an assessment of your organization’s exposure.

KEV checked 13 Nov 2026, 00:20 Jerusalem · Original catalog ↗

Reported products and versions

Linux Kernel / Kernel

Default status: Not specified

  • affected: unspecified to < 5.4.168 (custom)
  • affected: unspecified to < 5.10.88 (custom)
  • affected: unspecified to < 5.15.11 (custom)
  • affected: unspecified to < 5.16-rc6 (custom)

Fixes and workarounds

No explicit solution text in the downloaded CVE record. Consult the vendor advisory; unaffected version ranges are shown above as reported, not inferred as a patch recommendation.

Sources and related reporting

CVE Program record ↗ · Download tracked evidence as JSON

Observed change timeline

History begins when Egret first downloads each source. It is not the complete upstream CVE history.

12 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-12",
  "epss": 0.06586,
  "percentile": 0.93928
}
10 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-10",
  "epss": 0.06586,
  "percentile": 0.93892
}
09 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-09",
  "epss": 0.06586,
  "percentile": 0.93883
}
08 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-08",
  "epss": 0.06586,
  "percentile": 0.93881
}
07 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-07",
  "epss": 0.06586,
  "percentile": 0.93877
}
06 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-06",
  "epss": 0.06586,
  "percentile": 0.93869
}
06 Nov 2026, 06:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-05",
  "epss": 0.06586,
  "percentile": 0.93862
}
06 Nov 2026, 00:20 Jerusalem · CVE Program record changed

Stored CNA snapshot at this observation.

{
  "containers": {
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        "references": [
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            "url": "https://www.debian.org/security/2022/dsa-5096"
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            "tags": [
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            "url": "https://security.netapp.com/advisory/ntap-20230110-0002/"
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        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
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              "content": {
                "id": "CVE-2021-22600",
                "options": [
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                "role": "CISA Coordinator",
                "timestamp": "2025-01-29T20:47:54.395065Z",
                "version": "2.0.3"
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          {
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            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:L/A:H",
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04 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-04",
  "epss": 0.06586,
  "percentile": 0.93859
}
03 Nov 2026, 18:20 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-03",
  "epss": 0.06586,
  "percentile": 0.93848
}
03 Nov 2026, 02:22 Jerusalem · EPSS observation updated

Stored EPSS snapshot at this observation.

{
  "date": "2026-11-02",
  "epss": 0.06586,
  "percentile": 0.9384
}
03 Nov 2026, 02:22 Jerusalem · CISA KEV status changed

Stored KEV snapshot at this observation.

{
  "cveID": "CVE-2021-22600",
  "cwes": [
    "CWE-415"
  ],
  "dateAdded": "2022-04-11",
  "dueDate": "2022-05-02",
  "forensicTriage": "No",
  "knownRansomwareCampaignUse": "Unknown",
  "notes": "https://nvd.nist.gov/vuln/detail/CVE-2021-22600",
  "product": "Kernel",
  "requiredAction": "Apply updates per vendor instructions.",
  "shortDescription": "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.",
  "vendorProject": "Linux",
  "vulnerabilityName": "Linux Kernel Privilege Escalation Vulnerability"
}
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