Bug 1683150 (CVE-2018-20796) - CVE-2018-20796 glibc: uncontrolled recursion in function check_dst_limits_calc_pos_1 in posix/regexec.c
Summary: CVE-2018-20796 glibc: uncontrolled recursion in function check_dst_limits_cal...
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2018-20796
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1683153
Blocks: 1683152
TreeView+ depends on / blocked
 
Reported: 2019-02-26 10:47 UTC by Dhananjay Arunesh
Modified: 2019-09-29 15:08 UTC (History)
13 users (show)

Fixed In Version:
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Last Closed: 2019-06-10 10:48:50 UTC


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Description Dhananjay Arunesh 2019-02-26 10:47:05 UTC
In the GNU C Library (aka glibc or libc6) through 2.29, check_dst_limits_calc_pos_1 in posix/regexec.c has Uncontrolled Recursion, as demonstrated by '(\227|)(\\1\\1|t1|\\\2537)+' in grep.

Reference:
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34141

Comment 1 Dhananjay Arunesh 2019-02-26 10:49:10 UTC
Created glibc tracking bugs for this issue:

Affects: fedora-all [bug 1683153]

Comment 2 Florian Weimer 2019-02-26 11:00:38 UTC
The regular expression compiler in glibc is only supposed to be exposed to trusted content, so this is not a security vulnerability:

“resource exhaustion issues which can be triggered only with crafted patterns (either during compilation or execution) are not treated as security bugs”

<https://sourceware.org/glibc/wiki/Security%20Exceptions>

Comment 3 Huzaifa S. Sidhpurwala 2019-03-06 05:41:51 UTC
Statement:

The regular expression compiler in glibc is only supposed to be exposed to trusted content, therefore this flaw is not classified as a security vulnerability.


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