CVE-2019-20454
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.56%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.56% probability · 75th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- pcre/pcre2 · fedoraproject/fedora · splunk/universal forwarder
- Source
- cve@mitre.org
EPSS 1.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugs.exim.org/show_bug.cgi?id=2421Issue Tracking, Permissions Required, Third Party Advisory
- https://bugs.php.net/bug.php?id=78338Exploit, Issue Tracking, Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1735494Issue Tracking, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/03/msg00014.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQRAHYHLRNMBTPR3KXVM27NSZP3KTOPI/Mailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202006-16Third Party Advisory
- https://vcs.pcre.org/pcre2?view=revision&revision=1092Broken Link, Patch
- https://bugs.exim.org/show_bug.cgi?id=2421Issue Tracking, Permissions Required, Third Party Advisory
- https://bugs.php.net/bug.php?id=78338Exploit, Issue Tracking, Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1735494Issue Tracking, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2023/03/msg00014.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQRAHYHLRNMBTPR3KXVM27NSZP3KTOPI/Mailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202006-16Third Party Advisory
- https://vcs.pcre.org/pcre2?view=revision&revision=1092Broken Link, Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.