CVE record · CVE-2026-42533

NGINX Map directive and Regex matching vulnerability

CVSS 9.2 CriticalCriticalEPSS 0.063 · 93rd percentile

Critical, because:

CVSS score 9.2: 9.0 or more.

Published by the CVE Program (CNA: f5) at 15 Jul 2026, 14:33 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
F5	NGINX Plus	affected 37.0.0.1 to before 37.0.3.1 custom affected R36 to before R36 P7 custom affected R33 to before * custom Other versions: unknown
F5	NGINX Open Source	affected 1.31.2 to before 1.31.3 custom affected 0.9.6 to before 1.30.4 custom Other versions: unknown

Identifiers: CVE-2026-42533
CNA: f5
Weakness (CWE): CWE-122
Tags: F5 NGINX Plus
F5 NGINX Open Source
Memory corruption
Published: 15 Jul 2026
Updated: 3 Nov 2026

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.1	High	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	CNA (f5)
9.2	Critical	4.0	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (f5)Used for this record

CISA KEV Not listed.
EPSS 0.063, the 93rd percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

15 Jul 2026, 14:33 UTC Confirmed by the CVE List
15 Jul 2026, 15:16 UTC Confirmed by NVD

Sources

References from the CNA

my.f5.com/manage/s/article/K000162097 vendor-advisorypatch

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.