CVE-2021-37750

The Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.18.5 and 1.19.x before 1.19.3 has a NULL pointer dereference in kdc/do_tgs_req.c via a FAST inner body that lacks a server field.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
krb5	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Ignored
	21.04 hirsute	Ignored
	20.04 LTS focal	Fixed 1.17-6ubuntu4.3
	18.04 LTS bionic	Fixed 1.16-2ubuntu0.4
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

ccdm94

this vulnerability was introduced by commit 39548a5, as established by upstream. Prior to this commit, an error would occur instead of the null deference. In the patch notes, the CVE is described as affecting releases 1.14 and later only (meaning that xenial and trusty are not affected by this).

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
krb5	Upstream: d775c95

Severity score breakdown

Parameter	Value
Base score	6.5 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-5959-1
Kerberos vulnerabilities
16 March 2023