CVE-2026-56742
Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces
Description
Cilium is a networking, observability, and security solution. Prior to 1.17.17, 1.18.11, and 1.19.5, Cilium clusters using Gateway API allow users with permissions to create or update namespaced HTTPRoutes to mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism. Gateway API functionality is disabled by default. This issue is fixed in versions 1.17.17, 1.18.11, and 1.19.5.
INFO
Published Date :
July 15, 2026, 8:17 p.m.
Last Modified :
July 17, 2026, 5:48 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update Cilium to 1.17.17 or later.
- Update Cilium to 1.18.11 or later.
- Update Cilium to 1.19.5 or later.
- Ensure Gateway API functionality is disabled if not needed.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56742.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56742 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56742
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56742 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56742 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jul. 17, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L Added CPE Configuration OR *cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:* versions up to (excluding) 1.17.17 *cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:* versions from (including) 1.18.0 up to (excluding) 1.18.11 *cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:* versions from (including) 1.19.0 up to (excluding) 1.19.5 Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb Types: Patch Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b Types: Patch Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca Types: Patch Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/releases/tag/v1.17.17 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/releases/tag/v1.18.11 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/releases/tag/v1.19.5 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmj Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 16, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-56742', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-16T12:56:22.128191Z'} -
New CVE Received by [email protected]
Jul. 15, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'cilium', 'product': 'cilium', 'versions': [{'status': 'affected', 'version': '< 1.17.17'}, {'status': 'affected', 'version': '>= 1.18.0, < 1.18.11'}, {'status': 'affected', 'version': '>= 1.19.0, < 1.19.5'}]}] Added Description Cilium is a networking, observability, and security solution. Prior to 1.17.17, 1.18.11, and 1.19.5, Cilium clusters using Gateway API allow users with permissions to create or update namespaced HTTPRoutes to mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism. Gateway API functionality is disabled by default. This issue is fixed in versions 1.17.17, 1.18.11, and 1.19.5. Added CVSS V3.1 AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L Added CWE CWE-862 Added Reference https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb Added Reference https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857 Added Reference https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b Added Reference https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca Added Reference https://github.com/cilium/cilium/releases/tag/v1.17.17 Added Reference https://github.com/cilium/cilium/releases/tag/v1.18.11 Added Reference https://github.com/cilium/cilium/releases/tag/v1.19.5 Added Reference https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmj