Bug 1901041 (CVE-2020-28196)

Summary:	CVE-2020-28196 krb5: unbounded recursion via an ASN.1-encoded Kerberos message in lib/krb5/asn.1/asn1_encode.c may lead to DoS
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	csutherl, dfediuck, dpal, eedri, fdvorak, gzaronik, jclere, jplans, jwon, krathod, lgao, mbabacek, mgoldboi, michal.skrivanek, mturk, myarboro, nalin, pjindal, rharwood, sbonazzo, scorneli, security-response-team, sherold, weli
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	krb5 1.17.2, krb5 1.18.3	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in krb5. MIT Kerberos 5 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite lengths lacks a recursion limit.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-05-18 14:36:14 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1902657, 1906492
Bug Blocks:	1901042

Description Marian Rehak 2020-11-24 10:55:14 UTC

MIT Kerberos 5 (aka krb5) before 1.17.2 and 1.18.x before 1.18.3 allows unbounded recursion via an ASN.1-encoded Kerberos message because the lib/krb5/asn.1/asn1_encode.c support for BER indefinite lengths lacks a recursion limit.

Upstream Reference:

https://krbdev.mit.edu/rt/Ticket/Display.html?id=8959

Comment 1 Stefan Cornelius 2020-11-24 12:30:54 UTC

Patch:
https://github.com/krb5/krb5/commit/57415dda6cf04e73ffc3723be518eddfae599bfd

Comment 5 Sandro Bonazzola 2020-12-02 08:47:55 UTC

Any plan to get this fixed in RHEL 8? I see 1.18.2 shipped in RHEL 8.3 so it should be affected right?

Comment 12 errata-xmlrpc 2021-05-18 13:32:17 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:1593 https://access.redhat.com/errata/RHSA-2021:1593

Comment 13 Product Security DevOps Team 2021-05-18 14:36:14 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-28196

Comment 14 errata-xmlrpc 2021-06-03 10:24:21 UTC

This issue has been addressed in the following products:

  Red Hat Virtualization 4 for Red Hat Enterprise Linux 8

Via RHSA-2021:2239 https://access.redhat.com/errata/RHSA-2021:2239