SB2018010551 - Fedora EPEL 6 update for heimdal
Published: January 5, 2018 Updated: April 24, 2025
Security Bulletin ID
SB2018010551
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) NULL pointer dereference (CVE-ID: CVE-2017-17439)
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
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.
Remediation
Install update from vendor's website.