CVE-2018-20796 — In the GNU C Library (aka glibc or libc6) through 2

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.

01What is this vulnerability?

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.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-02-26T02:00:00.000Z
• Last modified: 2024-08-05T12:12:28.627Z

09References

• security.netapp.com — https://security.netapp.com/advisory/ntap-20190315-0002/
• lists.gnu.org — https://lists.gnu.org/archive/html/bug-gnulib/2019-01/msg00108.html
• www.securityfocus.com — http://www.securityfocus.com/bid/107160
• debbugs.gnu.org — https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34141
• support.f5.com — https://support.f5.com/csp/article/K26346590?utm_source=f5support&amp%3Butm_medi…