CVE-2021-36222 — ec_verify in kdc/kdc_preauth_ec.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka...

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

• Documented patch — github.com (NIST National Vulnerability Database)
• Documented patch — www.oracle.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Debian Debian Linux, Mit Kerberos 5, Netapp Active Iq Unified Manager…).
2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
3. Apply the fixed version or the patch documented under Remediation.
4. EPSS ahead of 96% of scored CVEs: prioritize it in the patch queue.
5. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-476 · NULL Pointer Dereference

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 10.51%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

Timeline

What happened to this CVE, newest first.

• 2026
• Record published
  Oct 14, 2026
• Fix documented
  Oct 14, 2026 · NIST National Vulnerability Database
• Affected products added · mit/kerberos 5, debian/debian linux, netapp/active iq unified manager, netapp/oncommand insight, netapp/oncommand workfl
  Oct 14, 2026 · NIST National Vulnerability Database
• CVSS changed · 7.5
  Oct 14, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 14, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 14, 2026 · Alertas do Telegram
• 2021
• CVE published
  Jul 22, 2021 · mitre

Source activity

Repeated readings are counted rather than listed.

• 2× References added · Oct 14, 2026 – Oct 14, 2026
• 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

10 on the record

• github.com/krb5/krb5/commit/fc98f520caefff2e5ee9a0026fdf5109944b3562
  Patch, Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuoct2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• github.com/krb5/krb5/releases
  Release Notes, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• cert-portal.siemens.com/productcert/html/ssa-398330.html
  NIST National Vulnerability Database
• github.com/advisories/GHSA-7gwg-3h62-pwf5
  GitHub Security Advisories
• www.debian.org/security/2021/dsa-4944
  Third Party Advisory, vendor-advisory, x_refsource_DEBIAN, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20211104-0007/
  Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• nvd.nist.gov/vuln/detail/CVE-2021-36222
  GitHub Security Advisories
• web.mit.edu/kerberos/advisories/
  Not Applicable, x_refsource_MISC, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20211022-0003/
  Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
• Medium CVE-2026-61144 Uncontrolled Resource Consumption in Oracle Mysql Server Jul 21, 2026
• Medium CVE-2026-61128 Uncontrolled Resource Consumption in Oracle Mysql Server Jul 21, 2026
• Medium CVE-2026-61109 Uncontrolled Resource Consumption in Oracle Mysql Server Jul 21, 2026
• Medium CVE-2026-61108 Uncontrolled Resource Consumption in Oracle Mysql Server Jul 21, 2026
• High CVE-2026-61094 Improper Privilege Management in Oracle Mysql Server Jul 21, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No CISA SSVC assessment.
• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2021-36222 is "ec_verify in kdc/kdc_preauth_ec.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka...", rated High. It affects Debian Linux (Debian); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 10.51% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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