CVE-2021-43824

Null pointer dereference in envoy

HIGH

7.5

CVSS Score

Published: February 22, 2022 at 10:15 PM UTC

Updated: June 17, 2026 at 04:11 AM UTC

1 product affected across 1 vendorEnvoy

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Severity

HIGH7.5

Exploit prediction

EPSS 1%

SSVC

No known exploit

Description

Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions a crafted request crashes Envoy when a CONNECT request is sent to JWT filter configured with regex match. This provides a denial of service attack vector. The only workaround is to not use regex in the JWT filter. Users are advised to upgrade.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Envoy · Envoyproxy

95%

v < 1.18.6v < 1.19.3v < 1.20.2v < 1.21.11.19.0 ≤ v < 1.19.31.20.0 ≤ v < 1.20.21.21.0 ≤ v < 1.21.1

Affected range stops below 1.18.6, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.19.3, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.20.2, so it looks safe — our inference, not a vendor statement

Affected range stops below 1.21.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a

References (2)

x_refsource_MISCPatchThird Party Advisory

Source: [email protected]

https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a

x_refsource_CONFIRMIssue TrackingThird Party Advisory

Source: [email protected]

https://github.com/envoyproxy/envoy/security/advisories/GHSA-vj5m-rch8-5r2p

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M

Attack Vector: NETWORK
Complexity: LOW
Privileges: NONE
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: NONE
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-476

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