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.
CVE-2021-32783
“—” beside the score: it is equal to NVD's CVSS score.
Score 8.5 from GitHub Security Advisory (severity: HIGH) published 2021-08-30. NVD baseline CVSS 8.5; sources differ by 0.0.
Also known asEUVD-2021-1578 (ENISA EUVD) · GHSA-5ph6-qq5x-7jwc (GitHub Security Advisories) · GO-2022-0922 (OSV.dev)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 8.5
- EG Score
- 8.5HIGHmedium confidence
- EG Risk
- 39EG Risk 39/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity85% × 45%Impact severity (EG Severity): CVSS 8.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation1.1% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 1.2%
- EPSS %ILE
- 66th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.5): severity, escalated by confirmed exploitation. This CVE's 8.5 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 1.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-31). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
July 23, 2021
Last Modified
November 21, 2024
Advisory Details (3)
Auto-updated Sep 2, 2026ExternalName Services can be used to gain access to Envoy's admin interface · Advisory · projectcontour/contour · GitHub
https://github.com/projectcontour/contour/security/advisories/GHSA-5ph6-qq5x-7jwcContour v1.17.1
Patch available: projectcontour/contour v1.17.1
https://github.com/projectcontour/contour/releases/tag/v1.17.1commit b53a5c4fd927 (projectcontour/contour)
Fix landed in projectcontour/contour commit b53a5c4fd927 — awaiting tagged release
https://github.com/projectcontour/contour/commit/b53a5c4fd927f4ea2c6cf02f1359d8e28bef852ePatch Availability(4)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| go | github.com/projectcontour/contour @ 1.14.2 (fixes < 1.14.2) | — | ghsa |
| go | github.com/projectcontour/contour @ 1.15.2 (fixes >= 1.15.0, < 1.15.2) | — | ghsa |
| go | github.com/projectcontour/contour @ 1.16.1 (fixes = 1.16.0) | — | ghsa |
| go | github.com/projectcontour/contour @ 1.17.1 (fixes = 1.17.0) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
Go(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| github.com/projectcontour/contour | 1.17.0 |
| — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 11× in last 7d / 39× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 94 of 215 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 6 repeat rows among the latest 100 are merged into the row they repeat. The 121 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-01 16:29 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-11-01 08:32 UTCGHSA enrichmentGHSA-5ph6-qq5x-7jwc · GitHub severity HIGH · GitHub CVSS 8.5
- 2026-11-01 08:32 UTCEG score recompute
- 2026-10-31 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-30 16:30 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-29 16:29 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-29 04:01 UTCEG score recompute
- 2026-10-29 03:55 UTCOSV refresh
- 2026-10-28 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-27 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-26 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-25 18:27 UTCEG score recompute
- 2026-10-25 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-24 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-23 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-22 16:29 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-21 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-21 09:39 UTCEG score recompute
- 2026-10-20 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-19 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-18 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-18 09:01 UTCEG score recompute
- 2026-10-18 07:25 UTCOSV refresh
- 2026-10-17 16:29 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-16 16:33 UTCEPSS rescoreEPSS 1.2% · 66th percentile
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- 2026-10-15 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
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- 2026-10-13 16:28 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-12 19:16 UTCEG score recompute
- 2026-10-12 16:29 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-11 23:41 UTCEG score recompute
- 2026-10-11 13:43 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-10-10 19:56 UTCEPSS rescoreEPSS 1.2% · 65th percentile
- 2026-10-09 20:04 UTCEPSS rescoreEPSS 1.2% · 65th percentile
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- 2026-10-01 19:46 UTCEPSS rescoreEPSS 1.2% · 65th percentile
- 2026-09-30 15:36 UTCEG score recompute
- 2026-09-30 15:00 UTCEPSS rescoreEPSS 1.2% · 65th percentile
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- 2026-09-28 13:47 UTCEPSS rescoreEPSS 1.2% · 65th percentile
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- 2026-09-26 00:21 UTCEPSS rescoreEPSS 1.2% · 65th percentile
- 2026-09-25 21:45 UTCOSV refresh
- 2026-09-24 14:00 UTCEPSS rescoreEPSS 1.2% · 65th percentile
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- 2026-09-06 13:45 UTCEPSS rescoreEPSS 1.2% · 64th percentile
- 2026-09-06 12:00 UTCOSV refresh
- 2026-09-05 15:25 UTCEPSS rescoreEPSS 1.2% · 64th percentile
- 2026-09-04 13:57 UTCEPSS rescoreEPSS 1.2% · 64th percentile
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- 2026-08-20 22:52 UTCEPSS rescoreEPSS 1.2% · 64th percentile
- 2026-08-19 22:45 UTCOSV refresh
- 2026-08-19 17:01 UTCEPSS rescoreEPSS 1.2% · 64th percentile
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Related CVEs(same product + same CWE)
Same product
2 shownGo:github.com/projectcontour/contour
Frequently asked(5)
What is CVE-2021-32783?
When was the CVE record for CVE-2021-32783 published?
Is CVE-2021-32783 actively exploited?
What is the CVSS score of CVE-2021-32783?
How do I remediate CVE-2021-32783?
Dependency Blast Radius
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