Denial of service in PCRE2

1) Out-of-bounds read

EUVDB-ID: #VU29116

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2019-20454

CWE-ID: CWE-125 - Out-of-bounds read

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to perform denial of service (DoS) attack.

The vulnerability exists due to a boundary condition in the "do_extuni_no_utf in pcre2_jit_compile.c" file when the pattern X is JIT compiled and used to match specially crafted subjects in non-UTF mode. A remote attacker can trigger out-of-bounds read error and crash the affected application.

Mitigation

Install update from vendor's website.

Vulnerable software versions

PCRE2: 10.00 - 10.33

CPE2.3

• cpe:2.3:a:pcre:pcre2:10.00:*:*:*:*:*:*:*
• cpe:2.3:a:pcre:pcre2:10.10:*:*:*:*:*:*:*
• cpe:2.3:a:pcre:pcre2:10.20:*:*:*:*:*:*:*

External links

https://bugs.exim.org/show_bug.cgi?id=2421
https://bugs.php.net/bug.php?id=78338
https://bugzilla.redhat.com/show_bug.cgi?id=1735494
https://security.gentoo.org/glsa/202006-16
https://vcs.pcre.org/pcre2?view=revision&revision=1092

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.