CVE-2019-20454 Denial of service in n/a

Medium 5.1 Published 14 Feb 2020 Updated 5 Aug 2024

An out-of-bounds read in PCRE allows attackers to crash applications parsing untrusted input via crafted patterns.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2019-20454?

CVE-2019-20454 is a medium-severity denial of service vulnerability in Fedoraproject Fedora, published on 14 Feb 2020. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

An out-of-bounds read was discovered in PCRE before 10.34 when the pattern \X is JIT compiled and used to match specially crafted subjects in non-UTF mode. Applications that use PCRE to parse untrusted input may be vulnerable to this flaw, which would allow an attacker to crash the application. The flaw occurs in do_extuni_no_utf in pcre2_jit_compile.c.

Weakness: CWE-125

Which versions are affected by CVE-2019-20454?

It affects 3 products.

Linux distribution packages (21)

`pcre2` AlmaLinux:8	All versions	`10.32-2.el8`
`pcre2-devel` AlmaLinux:8	All versions	`10.32-2.el8`
`pcre2-tools` AlmaLinux:8	All versions	`10.32-2.el8`
`pcre2-utf16` AlmaLinux:8	All versions	`10.32-2.el8`
`pcre2-utf32` AlmaLinux:8	All versions	`10.32-2.el8`
`pcre2` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-debuginfo` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-debugsource` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-devel` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-tools-debuginfo` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-utf16` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-utf16-debuginfo` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-utf32` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-utf32-debuginfo` Red Hat:enterprise_linux:8::baseos	All versions	`0:10.32-2.el8`
`pcre2-debuginfo` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2-debugsource` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2-tools` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2-tools-debuginfo` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2-utf16-debuginfo` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2-utf32-debuginfo` Red Hat:enterprise_linux:8::crb	All versions	`0:10.32-2.el8`
`pcre2` Rocky Linux:8	All versions	`0:10.32-2.el8`

Products include Fedoraproject Fedora, Pcre Pcre2, Splunk Universal Forwarder.

How do I fix CVE-2019-20454?

Upgrade to a fixed version.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2019-20454 being exploited?

There is no known exploitation of CVE-2019-20454 in the wild and no public exploit code.

All Fedoraproject Fedora vulnerabilities

Sources

Also known as ALSA-2020:4539, DEBIAN-CVE-2019-20454, GHSA-6wcm-vmc4-h93p, MGASA-2020-0305, RHSA-2020:4539, RLSA-2020:4539 and 1 more.