CVE-2026-56743 json
Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match
published 2026-07-15 3 mo ago modified 2026-09-10 59 d ago also BIT-cilium-2026-56743 , BIT-cilium-operator-2026-56743 , BIT-hubble-relay-2026-56743 , EUVD-2026-44774 , GHSA-fm8w-2m5w-9j7r , GO-2026-6367
- cvss
- 5.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 16%
- public exploits
- 0
- none known
Summary
Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.
Patch / fix
- go github.com/cilium/cilium 1.19.5
- bitnami cilium 1.19.5
- bitnami cilium-operator 1.19.5
- bitnami hubble-relay 1.19.5
- cilium cilium 1.19.5
- govulncheck-vulndb SLES 16.0, SLES for SAP applications 16.0 0.0.20260916T180043-160000.1.1
suse advisories SUSE-SU-2026:23855-1SUSE-SU-2026:23863-1
- govulncheck-vulndb openSUSE Leap 16.0 0.0.20260916T180043-160000.1.1
opensuse advisories openSUSE-SU-2026:21897-1
- github.com/cilium/cilium@1c84ae3 commit
- github.com/cilium/cilium@bacea64 commit
- github.com/cilium/cilium#46305 pull request
- github.com/cilium/cilium#46456 pull request
- github.com/cilium/cilium/releases/tag/v1.19.5 release
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.25% chance of exploitation in the next 30 days, higher than 16% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.4 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| GitHub | 3.1 | 5.4 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| OSV | 3.1 | 5.4 | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/cilium/cilium | >=1.19.0, <1.19.5 |
1.19.5 |
| bitnami | cilium | >=1.19.0, <1.19.5 |
1.19.5 |
| bitnami | cilium-operator | >=1.19.0, <1.19.5 |
1.19.5 |
| bitnami | hubble-relay | >=1.19.0, <1.19.5 |
1.19.5 |
Affected products
- cilium cilium
Classification
- Weakness
-
- CWE-863 Incorrect Authorization
References
-
github.com
/cilium/cilium/pull/46305
web, patch
-
github.com
/cilium/cilium/pull/46456
web, patch
-
github.com
/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8
web, patch
-
github.com
/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171
web, patch
-
github.com
/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r
web, vendor-advisory, advisory
-
github.com
/cilium/cilium/releases/tag/v1.19.5
web, release-notes, article
-
nvd.nist.gov
/vuln/detail/CVE-2026-56743
advisory, web
-
github.com
/cilium/cilium
package
Sources
- CVE List CVE-2026-56743
- GitHub Advisory GHSA-fm8w-2m5w-9j7r
- NVD CVE-2026-56743
- OSV BIT-cilium-2026-56743
- OSV BIT-cilium-operator-2026-56743
- OSV BIT-hubble-relay-2026-56743
- OSV GO-2026-6367
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.