CVE-2021-32780
No exploitation reported by the sources we read.
- Published2021-08-24
- Fixed in1.19.1 · 1.18.4
- WeaknessCWE-754
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
Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In affected versions Envoy transitions a H/2 connection to the CLOSED state when it receives a GOAWAY frame without any streams outstanding. The connection state is transitioned to DRAINING when it receives a SETTING frame with the SETTINGS_MAX_CONCURRENT_STREAMS parameter set to 0. Receiving these two frames in the same I/O event results in abnormal termination of the Envoy process due to invalid state transition from CLOSED to DRAINING. A sequence of H/2 frames delivered by an untrusted upstream server will result in Denial of Service in the presence of untrusted **upstream** servers. Envoy versions 1.19.1, 1.18.4 contain fixes to stop processing of pending H/2 frames after connection transition to the CLOSED state.
Timeline
dates in UTC- 2021-08-2421:15CVE 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-2021-32780?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-32780?format=csv
- TAXII collection of exploited CVEs
- The EDL and CSV take an API key on the Pro plan.
Versions per branch
OSV · NVD| Branch | Affected | Fixed in | Source |
|---|---|---|---|
| 1.19 | ≥ 1.19.0, < 1.19.1 | 1.19.1 | OSV |
| 1.18 | ≥ 1.18.0, < 1.18.4 | 1.18.4 | NVD · OSV |
| 1.19 | = 1.19.0 | no fix published | NVD |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Fix
- Update Envoy to 1.19.1 · 1.18.4
Advisories and patches
- www.envoyproxy.ioVendor Advisory
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:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2021-08-24
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-32780?
Is CVE-2021-32780 actively exploited?
What is the CVSS score for CVE-2021-32780?
Running Envoy? Hear about its next vulnerability
Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».
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Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
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Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.