# CVE-2019-20454: CVE-2019-20454

Status: published. Published: 2020-02-14. Updated: 2026-11-02.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- n/a / n/a: Version not specified (affected). Source: CNA: mitre

## Severity and prioritization

- CVSS 3.0: 5.1 (medium); CVSS:3.0/AC:H/AV:L/A:H/C:N/I:N/PR:N/S:U/UI:N; source: CNA: mitre

- CISA KEV: No listing in collected sources

- EPSS: 1.56% as of 2026-11-02; percentile 75.24%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://bugs.exim.org/show_bug.cgi?id=2421 (CNA: mitre)

- https://bugs.php.net/bug.php?id=78338 (CNA: mitre)

- https://vcs.pcre.org/pcre2?view=revision&revision=1092 (CNA: mitre)

- https://bugzilla.redhat.com/show_bug.cgi?id=1735494 (CNA: mitre)

- https://security.gentoo.org/glsa/202006-16 (CNA: mitre; vendor-advisory)

- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQRAHYHLRNMBTPR3KXVM27NSZP3KTOPI/ (CNA: mitre; vendor-advisory)

- https://lists.debian.org/debian-lts-announce/2023/03/msg00014.html (CNA: mitre; mailing-list)

- https://bugs.exim.org/show_bug.cgi?id=2421 (ADP: CVE; x_transferred)

- https://bugs.php.net/bug.php?id=78338 (ADP: CVE; x_transferred)

- https://vcs.pcre.org/pcre2?view=revision&revision=1092 (ADP: CVE; x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=1735494 (ADP: CVE; x_transferred)

- https://security.gentoo.org/glsa/202006-16 (ADP: CVE; vendor-advisory, x_transferred)

- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OQRAHYHLRNMBTPR3KXVM27NSZP3KTOPI/ (ADP: CVE; vendor-advisory, x_transferred)

- https://lists.debian.org/debian-lts-announce/2023/03/msg00014.html (ADP: CVE; mailing-list, x_transferred)

## Provenance

- CNA: mitre: https://www.cve.org/CVERecord?id=CVE-2019-20454; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2019-20454; retrieved 2026-11-02; source updated Not reported

Revision: 6f586d81d2a63abc8c013a44bd0e76cbd9f7c8570d36a9344573cef639440e64

Canonical: https://y2.dev/cve/CVE-2019-20454

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