CVE-2019-20838

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-06-15 · updated 2026-10-08
Weakness: CWE-125

Description

libpcre in PCRE before 8.43 allows a subject buffer over-read in JIT when UTF is disabled, and \X or \R has more than one fixed quantifier, a related issue to CVE-2019-20454.

Affected products

Apple macOS: before 11.0.1 — fixed in 11.0.1
Pcre: before 8.43 — fixed in 8.43
Splunk Universal Forwarder: from 8.2.0 before 8.2.12; from 9.0.0 before 9.0.6; 9.1.0 — fixed in 8.2.12, 9.0.6

How to fix

Upgrade to a fixed version: Apple macOS 11.0.1; Pcre 8.43; Splunk Universal Forwarder 8.2.12, 9.0.6. Check the vendor advisory for mitigations.

References

http://seclists.org/fulldisclosure/2020/Dec/32
http://seclists.org/fulldisclosure/2021/Feb/14
https://bugs.gentoo.org/717920
https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
https://support.apple.com/kb/HT211931
https://support.apple.com/kb/HT212147
https://www.pcre.org/original/changelog.txt
http://seclists.org/fulldisclosure/2020/Dec/32
http://seclists.org/fulldisclosure/2021/Feb/14
https://bugs.gentoo.org/717920
https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
https://support.apple.com/kb/HT211931

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