Security readout for executives and security teams
Plain-English summary
This flaw can make an affected MIT Kerberos KDC fail when it receives a malformed FAST-related ticket request. If your organization depends on Kerberos for logins or service authentication, KDC disruption can interrupt access to many systems.
Executive priority
Treat this as a near-term authentication availability issue. Prioritize KDCs supporting business-critical logins, domain authentication, and service-to-service access, especially in environments with broad internal reachability.
Technical view
CVE-2021-37750 is a NULL pointer dereference in MIT krb5 KDC code kdc/do_tgs_req.c. A FAST inner body lacking a server field affects MIT Kerberos 5 before 1.18.5 and 1.19.x before 1.19.3.
Likely exposure
Exposure is most relevant where MIT Kerberos KDCs or downstream products embedding krb5 are reachable by users or systems requesting Kerberos tickets.
Exploitation context
The source bundle does not show CISA KEV listing, active exploitation, public exploit use, CVSS, or CWE data. The described impact is availability-focused, not data theft or privilege escalation.
Researcher notes
Evidence is strongest for upstream MIT krb5 version impact and downstream vendor updates. The bundle does not provide CVSS, exploit maturity, authentication prerequisites, or a complete affected-product matrix.
Mitigation direction
- Upgrade MIT krb5 to 1.18.5, 1.19.3, or a later vendor-supported release.
- Apply downstream security updates from Linux, appliance, or software vendors using krb5.
- Check vendor advisories for Oracle, NetApp, StarWind, Debian, and Fedora environments.
- Restrict unnecessary network access to KDC services according to existing Kerberos architecture.
Validation and detection
- Inventory all Kerberos KDC servers and products that bundle MIT krb5.
- Verify installed krb5 versions are not before 1.18.5 or affected 1.19.x builds.
- Review OS and vendor package advisories for patched krb5 builds.
- Check authentication service monitoring for unexplained KDC crashes or restarts.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-37750 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://web.mit.edu/kerberos/advisories/CVE reference
- https://github.com/krb5/krb5/releasesCVE reference
- FEDORA-2021-f2c8514f02CVE reference · vendor-advisory
- [debian-lts-announce] 20210930 [SECURITY] [DLA 2771-1] krb5 security updateCVE reference · mailing-list
- https://www.oracle.com/security-alerts/cpujul2022.htmlCVE reference
- https://github.com/krb5/krb5/commit/d775c95af7606a51bf79547a94fa52ddd1cb7f49CVE reference
- https://security.netapp.com/advisory/ntap-20210923-0002/CVE reference
- https://www.starwindsoftware.com/security/sw-20220817-0004/CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.