CVE-2026-55723: When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an

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HIGH 8.3WATCHLISTUPGRADE

CVE-2026-55723 is a high-severity flaw (CVSS 8.3) affecting nginx ingress controller. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an injection vulnerability exists in the configuration generator of NGINX Ingress Controller. Multiple user-controllable fields are written into the generated NGINX configuration without sanitization. An authenticated attacker with permission to create or modify these CRDs or annotations may craft values that inject arbitrary NGINX configur

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-76
Published	2026-07-15
Last modified	2026-10-24

Publisher (CNA): F5 Networks · Vendor: f5

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-15 15:16 UTCPublished CVE record published
2026-10-24 21:10 UTCUpdated Record last modified

f5 nginx ingress controller UPGRADE

Affected: >= 3.6.0 and <= 3.7.2 · >= 4.0.0 and <= 4.0.1 · >= 5.0.0 and < 5.5.2

Fixed in: 5.5.2

Safe to downgrade to: a release before 3.6.0

1. Check installed version

apt-cache policy nginx-ingress-controller || rpm -q nginx-ingress-controller || nginx-ingress-controller --version

2. UPGRADE to 5.5.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nginx-ingress-controller

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nginx-ingress-controller

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.6.0 (Debian / Ubuntu)

apt-cache madison nginx-ingress-controller sudo apt install nginx-ingress-controller=<VERSION_BEFORE_3.6.0> sudo apt-mark hold nginx-ingress-controller

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list nginx-ingress-controller sudo dnf downgrade nginx-ingress-controller-<VERSION_BEFORE_3.6.0> sudo dnf versionlock add nginx-ingress-controller

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-55723?

nginx ingress controller: upgrade to 5.5.2. Exact commands for each OS are on this page.

Is CVE-2026-55723 being exploited?

CVE-2026-55723 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-55723 affect?

CVE-2026-55723 affects nginx ingress controller. Severity is high (CVSS 8.3). When NGINX Ingress Controller is configured with Custom Resource Definitions (CRDs) or Ingress annotations, an injection vulnerability exists in the configuration generator of NGINX Ingress Controller. Multiple user-controllable fields are

How urgent is CVE-2026-55723?

Priority 45/100. High severity; On your watchlist

Software pages

nginx vulnerabilities · F5 BIG-IP vulnerabilities

Related CVEs

CVE-2026-52865 MEDIUM 6.5 UPGRADE When NGINX Ingress Controller processes Ingress or TransportServer resources, an authenticated, remote attacke
CVE-2026-60065 LOW 3.7 UPGRADE UPGRADE When NGINX Plus is configured to use the Message Queuing Telemetry Transport (MQTT) filter module (ngx_stream_

References

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