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CVE-2023-41333· NVD / CVE Program· CNA GitHub_M

Bypass of namespace restrictions in CiliumNetworkPolicy

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. An attacker with the ability to create or modify CiliumNetworkPolicy objects in a particular namespace is able to affect traffic on an entire Cilium cluster, potentially bypassing policy enforcement in other namespaces. By using a crafted `endpointSelector` that uses the `DoesNotExist` operator on the `reserved:init` label, the attacker can create policies that bypass namespace restrictions and affect the entire Cilium cluster. This includes potentially allowing or denying all traffic. This attack requires API server access, as described in the Kubernetes API Server Attacker section of the Cilium Threat Model. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. As a workaround an admission webhook can be used to prevent the use of `endpointSelectors` that use the `DoesNotExist` operator on the `reserved:init` label in CiliumNetworkPolicies.

HighCVSS 8.1 · v3.1—No exploit Fix available
Published
Sep 27, 2023
Updated
Jun 17, 2026
EPSS
0.5% · 40th percentile
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Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
32 / 40 · 8.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
8.1
CNA · GitHub_M
6.9
1.2 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

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Affected systems

VendorProduct
ciliumcilium

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • cilium ciliumbefore 1.12.14
  • cilium cilium1.13.0 and later · before 1.13.7
  • cilium cilium1.14.0 and later · before 1.14.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • cilium cilium

    • >= 1.14.0, < 1.14.2, >= 1.13.0, < 1.13.7, < 1.12.14affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Gogithub.com/cilium/ciliumfrom 1.13.0 · before 1.13.71.13.7
Gogithub.com/cilium/ciliumfrom 1.14.0 · before 1.14.21.14.2
Gogithub.com/cilium/ciliumbefore 1.12.141.12.14

Same product

cilium: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-27595Cilium eBPF filters may be temporarily removed during agent restart
    39Monitor
  • CVE-2023-39347Cilium NetworkPolicy bypass via pod labels
    36Monitor
  • CVE-2026-56742Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces
    35Monitor
  • CVE-2026-49445Cilium: Sensitive information disclosure and cluster disruption via local Envoy admin socket access
    35Monitor
  • CVE-2024-47825CIDR deny policies may not take effect when a more narrow CIDR allow is present
    34Monitor
  • CVE-2022-29179Improper Privilege Management in Cilium
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Go:github.com/cilium/cilium1.12.14Package registry (OSV)
Go:github.com/cilium/cilium1.13.7Package registry (OSV)
Go:github.com/cilium/cilium1.14.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • Administrator privileges are required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Adjacent
Attack complexity
Low
Privileges required
High
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

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

nvd-primary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
// Added for the support teamapp.post("/maintenance/reset", resetDevice);

Fixed

ts
if (config.maintenanceEnabled) {  app.post(    "/maintenance/reset",    requireSession, requireRole("admin"), resetDevice  );}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records