CVE-2021-43826
No exploitation reported by the sources we read.
- Published2022-02-22
- Fixed in1.21.1 · 1.20.2 · 1.19.3 · 1.18.6
- WeaknessCWE-416
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 edge and service proxy, designed for cloud-native applications. In affected versions of Envoy a crash occurs when configured for :ref:`upstream tunneling <envoy_v3_api_field_extensions.filters.network.tcp_proxy.v3.TcpProxy.tunneling_config>` and the downstream connection disconnects while the the upstream connection or http/2 stream is still being established. There are no workarounds for this issue. Users are advised to upgrade.
Timeline
dates in UTC- 2022-02-2223:15CVE 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-2021-43826?format=txt
- CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-43826?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 |
|---|---|---|---|
| 1.21 | ≥ 1.21.0, < 1.21.1 | 1.21.1 | NVD · OSV |
| 1.20 | ≥ 1.20.0, < 1.20.2 | 1.20.2 | NVD · OSV |
| 1.19 | ≥ 1.19.0, < 1.19.3 | 1.19.3 | NVD · OSV |
| 1.18 | < 1.18.6 | 1.18.6 | NVD · OSV |
as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.
Distribution builds and vendor advisories
Packages from OSV.dev and products from the vendors' CSAF advisories.
version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.
Vendor advisories
Red Hat Security Advisory: Red Hat OpenShift Service Mesh 2.0.9 security update
Fix
- Update Envoy to 1.21.1 · 1.20.2 · 1.19.3 · 1.18.6
- Vendor fix Red Hat Product Security RHSA-2022:1276 · 4 productsThe OpenShift Service Mesh release notes provide information on the features and known issues: https://docs.openshift.com/container-platform/latest/service_mesh/v2x/servicemesh-release-notes.html
Advisories and patches
- github.comPatch
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
- 2022-02-22
- Last Modified
- 2026-06-17
- NVD status
- Modified
Frequently asked questions
What is CVE-2021-43826?
Is CVE-2021-43826 actively exploited?
What is the CVSS score for CVE-2021-43826?
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 ».
No credit card required · No monthly cap on website lookups · 250 API requests/month
Go further
- Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
- Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.
Related vulnerabilities
Same product first, then the same vendor advisory and the same publication week.