Bug 1932589 (CVE-2021-27645) - CVE-2021-27645 glibc: Use-after-free in addgetnetgrentX function in netgroupcache.c
Summary: CVE-2021-27645 glibc: Use-after-free in addgetnetgrentX function in netgroupc...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-27645
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1927877 1932590 1933582
Blocks: 1932591
TreeView+ depends on / blocked
 
Reported: 2021-02-24 18:54 UTC by Pedro Sampaio
Modified: 2022-11-08 11:36 UTC (History)
18 users (show)

Fixed In Version: glibc 2.34
Doc Type: If docs needed, set a value
Doc Text:
The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6), when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system.
Clone Of:
Environment:
Last Closed: 2021-11-09 20:21:06 UTC
Embargoed:

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:4358 0 None None None 2021-11-09 18:28:13 UTC

Description Pedro Sampaio 2021-02-24 18:54:09 UTC 
The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.

Upstream bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=27462
Comment 1 Pedro Sampaio 2021-02-24 18:55:42 UTC 
Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1932590]
Comment 7 Huzaifa S. Sidhpurwala 2021-03-04 04:01:47 UTC 
Upstream patch: https://sourceware.org/git/?p=glibc.git;a=commit;h=dca565886b5e8bd7966e15f0ca42ee5cff686673
Comment 8 Huzaifa S. Sidhpurwala 2021-03-04 04:09:48 UTC 
Statement:

This is a local crash in nscd causing a performance penalty. It is constrained by needing a netgroup request to have a response larger than 1K to cause the double-free crash. Therefore this is not a full denial of service.
Comment 11 errata-xmlrpc 2021-11-09 18:28:11 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:4358 https://access.redhat.com/errata/RHSA-2021:4358
Comment 12 Product Security DevOps Team 2021-11-09 20:21:03 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-2021-27645
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