CVE-2026-42055

HIGHEPSS 93th pctl

8.1

CVSS v3

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based 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. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

CWE-122Heap-based Buffer Overflow CWE-787Out-of-bounds Write CWE-131

How to fix

Remediation Available

nginxDebian

Fixed in:1.18.0-6.1+deb11u8CVE-2026-42055

Fixed in:1.22.1-9+deb12u9CVE-2026-42055

Fixed in:1.26.3-3+deb13u7CVE-2026-42055

Fixed in:1.30.1-5CVE-2026-42055

nginxRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.aarch64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

nginxRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.src::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

nginx-all-modulesRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.noarch::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.noarch::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.noarch::nginx:1.26RHSA-2026:36639

Fixed in:2:1.20.1-28.el9_8.4RHSA-2026:36331

nginx-all-modulesRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.noarch::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.noarch::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.noarch::nginx:1.24RHSA-2026:36618

Fixed in:2:1.20.1-28.el9_8.4RHSA-2026:36331

nginx-coreRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.x86_64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

nginx-coreRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

nginx-core-debuginfoRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

nginx-core-debuginfoRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

nginx-debuginfoRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

nginx-debuginfoRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

nginx-debugsourceRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

nginx-debugsourceRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

nginx-filesystemRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.noarch::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.noarch::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.noarch::nginx:1.24RHSA-2026:38847

Fixed in:2:1.20.1-28.el9_8.4RHSA-2026:36331

nginx-filesystemRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.noarch::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.noarch::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.noarch::nginx:1.26RHSA-2026:36639

Fixed in:2:1.20.1-28.el9_8.4RHSA-2026:36331

nginx-mod-develRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

nginx-mod-develRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

nginx-mod-http-image-filterRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

nginx-mod-http-image-filterRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.aarch64::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

nginx-mod-http-image-filter-debuginfoRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

nginx-mod-http-image-filter-debuginfoRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

nginx-mod-http-perlRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.aarch64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

nginx-mod-http-perlRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

nginx-mod-http-perl-debuginfoRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.x86_64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

nginx-mod-http-perl-debuginfoRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

nginx-mod-http-xslt-filterRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.aarch64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.x86_64::nginx:1.24RHSA-2026:36618

nginx-mod-http-xslt-filterRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.x86_64::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

nginx-mod-http-xslt-filter-debuginfoRocky

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.ppc64le::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.aarch64::nginx:1.24RHSA-2026:38847

nginx-mod-http-xslt-filter-debuginfoRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.ppc64le::nginx:1.24RHSA-2026:36618

Fixed in:2:1.26.3-9.module+el9.8.0+24501+a1e882cd.2.s390x::nginx:1.26RHSA-2026:36639

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.aarch64::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.x86_64::nginx:1.24RHSA-2026:36618

nginx-mod-mailRed Hat / RHEL

Fixed in:2:1.26.3-6.el10_2.5RHSA-2026:36364

Fixed in:1:1.24.0-7.module+el9.8.0+24502+c9b9ab67.3.s390x::nginx:1.24RHSA-2026:36618

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.s390x::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.ppc64le::nginx:1.24RHSA-2026:38847

Fixed in:1:1.24.0-3.module+el8.10.0+24503+61c7c092.3.x86_64::nginx:1.24RHSA-2026:38847

This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

6.54%probability of exploitation in 30 days

93rdpercentile

High risk: more likely to be exploited than 93% of all known CVEs.

References

Vendor Advisory1

my.f5.com

Third-Party Advisory11

Other references1

access.redhat.com

Related Vulnerabilities

Other CWE-122 (Heap-based Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2015-3113	Critical	9.8	100%	KEV	Fix
CVE-2024-26256	High	7.8	88%	-	Fix
CVE-2020-25687	Medium	5.9	87%	-	Fix
CVE-2009-3459	High	8.8	87%	KEV	Fix
CVE-2021-21017	High	8.8	86%	KEV	-
CVE-2020-25683	Medium	5.9	86%	-	Fix

Common questions

How do I fix CVE-2026-42055?

Published advisories record a fix for 54 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-42055 being actively exploited?

Not that we know of. CVE-2026-42055 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 6.5% is the estimated probability that it will be exploited in the next 30 days. That is higher than 93% of all scored CVEs.

How severe is CVE-2026-42055?

CVE-2026-42055 has a CVSS v3 base score of 8.1, rated important. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-42055 affect?

Published advisories record a fix for nginx (Debian), nginx (Red Hat / RHEL), nginx (Rocky), nginx-all-modules (Red Hat / RHEL), and 50 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-25.