9.2

CVE-2026-42533: f5 nginx gateway fabric Heap-based Buffer Overflow

CVSS: 9.2v4.0CriticalAnalyzed
AliasesALPINE-CVE-2026-42533SUSE-SU-2026:23118-1SUSE-SU-2026:23140-1
Published 15-07-2026Last modified 29-07-2026
Open JSON

Vulnerability summary

CVE-2026-42533 is a critical (CVSS 9.2) Heap-based Buffer Overflow vulnerability in f5 nginx gateway fabric. EPSS estimates a 0.89% chance of exploitation in the next 30 days, higher than 58.7% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.2/10
010
Critical · v4.0 (CVE.org)
EPSS score
0.89%
0%100%
Low · -3.56 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 7
MGASA-2026-0301OPENSUSE-SU-2026:11295-1RHSA-2026:46012SUSE-SU-2026:3448-1CGA-8H29-23P8-WHF6USN-8563-1

Timeline

  1. 15-07-2026
    PublishedVulnerability first disclosed.
  2. 29-07-2026
    Last modifiedVulnerability information updated.

Description

A vulnerability exists in NGINX Plus and NGINX Open Source when a map directive uses regex matching and a string expression references the map's regex capture variables before referencing the map output variable. Alternatively, the same result could be achieved by using a non-cacheable variable in a string expression under certain conditions. An unauthenticated attacker along with conditions beyond their control can exploit this vulnerability by sending crafted HTTP requests. This may cause a heap buffer overflow in the NGINX worker process leading to a restart. Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Impact: This vulnerability may allow remote attackers to cause a denial-of-service (DoS) on the NGINX system or to possibly trigger a code execution. There is no control plane exposure; this is a data plane issue only.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CVSS metrics

11 scores · 8 sources · 2 versions

EPSS trend

Probability

0.89%

Chance of exploitation in the next 30 days

Percentile

59%

Versus all other CVEs

30-day change

-3.56 pp

From 4.45% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.89%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Redhat18 products
  • nginx< 2:1.20.1-28.el9_8.6 | < 2:1.26.3-9.module+el9.8.0+24845+a897661e.4 | < 1:1.24.0-7.module+el9.8.0+24846+e7eec568.5 | < 2:1.26.3-6.el10_2.7 | < 1:1.24.0-3.module+el8.10.0+24848+0300f002.5
  • nginx-all-modules< 2:1.20.1-28.el9_8.6 | < 2:1.26.3-9.module+el9.8.0+24845+a897661e.4 | < 1:1.24.0-7.module+el9.8.0+24846+e7eec568.5 | < 2:1.26.3-6.el10_2.7 | < 1:1.24.0-3.module+el8.10.0+24848+0300f002.5
  • nginx-core< 2:1.20.1-28.el9_8.6 | < 2:1.26.3-9.module+el9.8.0+24845+a897661e.4 | < 1:1.24.0-7.module+el9.8.0+24846+e7eec568.5 | < 2:1.26.3-6.el10_2.7
  • nginx-core-debuginfo< 2:1.20.1-28.el9_8.6 | < 2:1.26.3-9.module+el9.8.0+24845+a897661e.4 | < 1:1.24.0-7.module+el9.8.0+24846+e7eec568.5 | < 2:1.26.3-6.el10_2.7
  • nginx-debuginfo< 2:1.20.1-28.el9_8.6 | < 2:1.26.3-9.module+el9.8.0+24845+a897661e.4 | < 1:1.24.0-7.module+el9.8.0+24846+e7eec568.5 | < 2:1.26.3-6.el10_2.7 | < 1:1.24.0-3.module+el8.10.0+24848+0300f002.5
Chainguard6 products
  • commercial-nginx-plus< 37.0.3.1-r0
  • ingress-nginx-controller-1.15< 1.15.10-r0
  • ingress-nginx-controller-fips-1.15< 1.15.10-r0
  • nginx-mainline< 1.31.3-r0
  • nginx-stable< 1.30.4-r0
F55 products
  • nginx gateway fabric≥ 1.3.0, ≤ 1.6.2 | ≥ 2.0.0, < 2.6.7
  • nginx ingress controller≥ 3.5.0, ≤ 3.7.2 | ≥ 5.0.0, < 5.5.3 | ≥ 2026-lts-r1, < 2026-lts-r4 | 4.0.0 | 4.0.1
  • nginx open source≥ 1.31.2, < 1.31.3 | ≥ 0.9.6, < 1.30.4
  • nginx plus≥ R36, < R36 P7 | ≥ R33 (No fix recorded) | ≥ 37.0.0.1, < 37.0.3.1 | ≥ r33, < r36 | r36 | r36:p1 | r36:p2 | r36:p3 | r36:p4 | r36:p5 | r36:p6
  • waf≥ 4.11.0, ≤ 4.16.0 | ≥ 5.2.0, ≤ 5.8.0 | ≥ 5.9.0, < 5.13.4
Suse5 products
  • nginx&distro=SUSE Linux Enterprise Module for Server Applications 15 SP7< 1.21.5-150600.10.27.1
  • nginx&distro=SUSE Linux Enterprise Server 15 SP6-LTSS< 1.21.5-150600.10.27.1
  • nginx&distro=SUSE Linux Enterprise Server 16.0< 1.27.2-160000.7.1
  • nginx&distro=SUSE Linux Enterprise Server for SAP Applications 15 SP6< 1.21.5-150600.10.27.1
  • nginx&distro=SUSE Linux Enterprise Server for SAP applications 16.0< 1.27.2-160000.7.1
Wolfi4 products
  • ingress-nginx-controller-1.15< 1.15.10-r0
  • nginx-mainline< 1.31.3-r0
  • nginx-stable< 1.30.4-r0
  • nginx-stable-package-config< 1.30.4-r5
Alpine1 product
  • nginx< 1.26.3-r2 | < 1.28.3-r6 | < 1.30.4-r0
Debian1 product
  • nginx< 1.22.1-9+deb12u10 | < 1.26.3-3+deb13u8 | < 1.30.4-3
Opensuse1 product
  • nginx&distro=openSUSE Leap 16.0< 1.27.2-160000.7.1
Ubuntu1 product
  • nginxAll versions (No fix recorded) | < 1.18.0-6ubuntu14.21 | < 1.24.0-2ubuntu7.18 | < 1.28.3-2ubuntu1.11

9 vendors · 42 products

References

32 links
Show all 32 references