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CVE-2021-36222: ec_verify in kdc/kdc_preauth_ec.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before...

ec_verify in kdc/kdc_preauth_ec.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.4 and 1.19.x before 1.19.2 allows remote attackers to cause a NULL pointer dereference and daemon crash. This occurs because a return value is not properly managed in a certain situation.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A remote attacker could crash an MIT Kerberos KDC by triggering a NULL pointer dereference in pre-authentication handling. A KDC outage can interrupt authentication for services that depend on Kerberos. The provided sources do not show KEV listing, CVSS scoring, or active exploitation evidence.

Executive priority

Prioritize remediation where Kerberos supports business-critical authentication. This is not documented as actively exploited in the supplied sources, but a KDC crash can cause service access disruption across dependent systems.

Technical view

CVE-2021-36222 affects MIT krb5 KDC ec_verify in kdc/kdc_preauth_ec.c before 1.18.4 and 1.19.x before 1.19.2. Improper return-value handling can cause a NULL pointer dereference and KDC daemon crash, indicating a remote denial-of-service condition.

Likely exposure

Organizations running MIT krb5 KDC versions before 1.18.4, or 1.19.x before 1.19.2, are the clearest exposure. Downstream products or appliances from vendors such as Debian, Oracle, and NetApp may also be relevant if they embed or package affected krb5 components.

Exploitation context

The source bundle describes remote attack capability causing daemon crash. It does not provide exploit details, public exploitation claims, or KEV confirmation. Treat this as an availability risk against Kerberos authentication infrastructure, not as proven code execution or data compromise.

Researcher notes

The affected function and file are identified, and the linked krb5 commit is the main confirmation reference. CVSS, CWE, and detailed affected-product metadata are absent from the bundle, so severity should be bounded to documented remote denial of service.

Mitigation direction

  • Upgrade MIT krb5 KDC to 1.18.4, 1.19.2, or a later fixed release.
  • Apply vendor security updates for Debian, Oracle, NetApp, or other downstream platforms.
  • Check MIT Kerberos advisories and krb5 release notes for vendor-specific remediation details.
  • Prioritize resilient KDC deployment and monitoring where immediate patching is delayed.

Validation and detection

  • Inventory KDC hosts and identify MIT krb5 package or source versions.
  • Confirm no KDC is running before 1.18.4 or 1.19.x before 1.19.2.
  • Review vendor advisories for affected downstream product versions.
  • Check KDC service logs and uptime for unexplained daemon crashes.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
8Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.