In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by…
Priority LOW 39CWE-476Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- No fix listed
Attack profile from CVSS 3.0 · NVD. Fix status from CNA. Impact type from CWE-476.
Summary
In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.
Why it matters now
EPSS 0.03427 88th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* | 9.0 | Vulnerable | Debian |
| cpe:2.3:a:heimdal_project:heimdal:*:*:*:*:*:*:*:* | up to 7.4.0 | Vulnerable | Heimdal Project |
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
- cpe:2.3:a:heimdal_project:heimdal:*:*:*:*:*:*:*:* Versions up to 7.4.0 Vulnerable ·Heimdal Project
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2017-17439
- 2026-10-03 Alias added: GHSA-gc5p-r2vh-qc88
References
Advisory 4
Sources
- CVE-2017-17439 · CVE Program
- CVE-2017-17439 · NVD
- FIRST EPSS
- GHSA-gc5p-r2vh-qc88 · GitHub Advisory Database · CC BY 4.0
- CVE-2017-17439 · Red Hat security data · CC BY 4.0
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