CVE-2021-32783
No exploitation reported by the sources we read.
- Published2021-07-23
- Fixed in1.17.1 · 1.16.1 · 1.15.2 · 1.14.2
- WeaknessCWE-441 · CWE-610
Am I affected?
Debian, Ubuntu or Red Hat sometimes backport a fix without changing the upstream version number: such a version reads « to verify », never « affected ».With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.
Description
Contour is a Kubernetes ingress controller using Envoy proxy. In Contour before version 1.17.1 a specially crafted ExternalName type Service may be used to access Envoy's admin interface, which Contour normally prevents from access outside the Envoy container. This can be used to shut down Envoy remotely (a denial of service), or to expose the existence of any Secret that Envoy is using for its configuration, including most notably TLS Keypairs. However, it *cannot* be used to get the *content* of those secrets. Since this attack allows access to the administration interface, a variety of administration options are available, such as shutting down the Envoy or draining traffic. In general, the Envoy admin interface cannot easily be used for making changes to the cluster, in-flight requests, or backend services, but it could be used to shut down or drain Envoy, change traffic routing, or to retrieve secret metadata, as mentioned above. The issue will be addressed in Contour v1.18.0 and a cherry-picked patch release, v1.17.1, has been released to cover users who cannot upgrade at this time. For more details refer to the linked GitHub Security Advisory.
Timeline
dates in UTC- 2021-07-2322:15CVE publishedNVD
Observed activity
isMalicious corpus · updated 2026-10-23 21:37 UTCBlock these indicators
- Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-32783?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-32783?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
NVD · OSV| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.17 | < 1.17.1 | 1.17.1 | NVD · OSV |
| 1.17 | ≥ 1.17.0, < 1.17.1 | 1.17.1 | OSV |
| 1.16 | ≥ 1.16.0, < 1.16.1 | 1.16.1 | OSV |
| 1.15 | ≥ 1.15.0, < 1.15.2 | 1.15.2 | OSV |
| 1.14 | < 1.14.2 | 1.14.2 | OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Projectcontour contour to 1.17.1 · 1.16.1 · 1.15.2 · 1.14.2
Advisories and patches
- github.comPatch
- github.comRelease Notes
Detection
- Nuclei template
- none so far ProjectDiscovery
- Exploit-DB
- no entry Exploit-DB
- Proof-of-concept repositories
- none listed PoC-in-GitHub
Sources
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
- Published
- 2021-07-23
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-32783?
Is CVE-2021-32783 actively exploited?
What is the CVSS score for CVE-2021-32783?
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Related vulnerabilities
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