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Fencer Intel
medium 5.9

CVE-2026-56742 json

Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces

published 3mo ago modified last mo. also BIT-cilium-2026-56742 , BIT-cilium-operator-2026-56742 , BIT-hubble-relay-2026-56742 , EUVD-2026-44773 , GHSA-w7c2-w76w-5hmj , GO-2026-6596

cvss
5.9
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 7%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/cilium/cilium 1.17.17, 1.18.11, 1.19.5
  • go github.com/cilium/ciliumCilium 1.18.11
  • bitnami cilium 1.17.17, 1.18.11, 1.19.5
  • bitnami cilium-operator 1.17.17, 1.18.11, 1.19.5
  • bitnami hubble-relay 1.17.17, 1.18.11, 1.19.5
  • cilium cilium 1.17.17, 1.18.11, 1.19.5

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
3mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L
GitHub 3.1 5.9 CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L
NVD 3.1 8.9 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
OSV 3.1 8.9 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

Affected packages

ecosystem package affected fixed in
go github.com/cilium/cilium
<1.17.17
>=1.19.0, <1.19.5
>=1.18.0, <1.18.11
1.17.17
1.19.5
1.18.11
go github.com/cilium/ciliumCilium
>=1.18.0, <1.18.11
1.18.11
bitnami cilium
<1.17.17
>=1.18.0, <1.18.11
>=1.19.0, <1.19.5
1.17.17
1.18.11
1.19.5
bitnami cilium-operator
<1.17.17
>=1.18.0, <1.18.11
>=1.19.0, <1.19.5
1.17.17
1.18.11
1.19.5
bitnami hubble-relay
<1.17.17
>=1.18.0, <1.18.11
>=1.19.0, <1.19.5
1.17.17
1.18.11
1.19.5

Affected products

  • cilium cilium

Classification

Weakness

References

Sources

Fencer Intel 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.