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🛡️ CVE-2026-55723 — nginx-ingress-controller

🟠 CVSS 8.3 — High ✅ No Known Exploit CWE-76 NVD
8.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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 configuration directives.

Impact:

An authenticated attacker granted write access to NGINX Ingress Controller CRDs or Ingress annotations through the Kubernetes API may be able to inject arbitrary NGINX configuration directives, create or delete files, or disable services. There is no data plane exposure; this is a control plane issue only.

Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Weakness class

CVE-2026-55723 is classified as CWE-76: Improper Neutralization of Equivalent Special Elements. The product correctly neutralizes certain special elements, but it improperly neutralizes equivalent special elements.

Affected software

CVE-2026-55723 is recorded against 1 package.

  • nginx-ingress-controller (from 5.0.0 up to 5.5.2)

Timeline and source

Published on 15 July 2026 and last revised on 16 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

my.f5.com

Other advisories for this package

nginx-ingress-controller has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-76: Improper Neutralization of Equivalent Special Elements) in other software:

Details

Severity HIGH
CVSS Score 8.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
CWE CWE-76
Public Exploit ✅ No
Source NVD
Published 2026-07-15
Updated 2026-08-20
Modified 2026-07-16
Fix URL N/A

Affected Packages

Software From version Fixed in
nginx-ingress-controller 5.0.0 5.5.2

References

Mitigation, Vendor Advisory https://my.f5.com/manage/s/article/K000161800

Site Security Check

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CVE-2026-55723 is rated CVSS 8.3 High. BotEraser scans your installation against known CVE records and tells you whether this vulnerability applies to the versions you actually run.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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