9.8

CVE-2023-27595: Cilium eBPF filters may be temporarily removed during agent restart

Modified
AliasesGHSA-r5x6-w42p-jhppBIT-cilium-2023-27595BIT-cilium-operator-2023-27595
Published 17-03-2023Last modified 25-02-2025

Vulnerability summary

CVE-2023-27595 is a critical (CVSS 9.8) vulnerability in cilium. EPSS estimates a 0.73% chance of exploitation in the next 30 days, higher than 53.8% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
0.73%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 17-03-2023
    PublishedVulnerability first disclosed.
  2. 25-02-2025
    Last modifiedVulnerability information updated.

Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. In version 1.13.0, when Cilium is started, there is a short period when Cilium eBPF programs are not attached to the host. During this period, the host does not implement any of Cilium's featureset. This can cause disruption to newly established connections during this period due to the lack of Load Balancing, or can cause Network Policy bypass due to the lack of Network Policy enforcement during the window. This vulnerability impacts any Cilium-managed endpoints on the node (such as Kubernetes Pods), as well as the host network namespace (including Host Firewall). This vulnerability is fixed in Cilium 1.13.1 or later. Cilium releases 1.12.x, 1.11.x, and earlier are not affected. There are no known workarounds.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.73%

Chance of exploitation in the next 30 days

Percentile

54%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.73% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cilium1 product
Github.com/cilium1 product
  • cilium≥ 1.13.0, < 1.13.1

2 vendors · 2 products

References

5 links