Bug 1779573 (CVE-2019-19333) - CVE-2019-19333 libyang: stack-based buffer overflow in make_canonical when bits leaf type is used
Summary: CVE-2019-19333 libyang: stack-based buffer overflow in make_canonical when bi...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2019-19333
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: Engineering1780310 Engineering1780311 1780495
Blocks: Embargoed1778852
TreeView+ depends on / blocked
 
Reported: 2019-12-04 09:47 UTC by Riccardo Schirone
Modified: 2021-02-16 20:56 UTC (History)
3 users (show)

Fixed In Version: libyang 1.0-r5
Doc Type: If docs needed, set a value
Doc Text:
A stack-based buffer overflow flaw was discovered in the way libyang parses YANG files with a leaf of type "bits". An application that uses libyang to parse untrusted YANG files may be vulnerable to this flaw, which would allow an attacker to cause a denial of service or execute code.
Clone Of:
Environment:
Last Closed: 2019-12-23 14:09:50 UTC

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2019:4360 0 None None None 2019-12-23 03:56:45 UTC

Description Riccardo Schirone 2019-12-04 09:47:52 UTC 
libyang up to version 1 release 4 has a stack-based buffer overflow in function make_canonical() in parser.c, when dealing with "bits" types with a name longer than 511 bytes. An application that uses libyang to validate untrusted YANG files could be vulnerable to this flaw, which could be used by an attacker to cause a denial of service or possibly gain code execution.
Comment 1 Riccardo Schirone 2019-12-04 09:47:55 UTC 
Acknowledgments:

Name: Riccardo Schirone (Red Hat Product Security)
Comment 3 Riccardo Schirone 2019-12-04 13:33:16 UTC 
Upstream fix:
https://github.com/CESNET/libyang/commit/f6d684ade99dd37b21babaa8a856f64faa1e2e0d
Comment 5 Riccardo Schirone 2019-12-05 16:38:52 UTC 
An application that parses untrusted YANG files could be vulnerable to this flaw. To trigger this flaw, a YANG module should have a leaf with type "bits" and a default value longer than 511 bytes, which would cause a stack-based buffer overflow in make_canonical(), due to the insecure use of strcpy without any check.
Comment 7 Riccardo Schirone 2019-12-06 07:56:33 UTC 
Created libyang tracking bugs for this issue:

Affects: fedora-all [bug 1780495]
Comment 10 errata-xmlrpc 2019-12-23 03:56:44 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2019:4360 https://access.redhat.com/errata/RHSA-2019:4360
Comment 11 Product Security DevOps Team 2019-12-23 14:09:50 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-2019-19333
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