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CVE-2021-28682

25
FAUCET Score

CVE-2021-28682 is a remotely exploitable integer overflow vulnerability in Envoy versions up to 1.71.1. A very large grpc-timeout value can lead to incorrect timeout calculations, potentially causing a denial of service. It carries a CVSS score of 7.5 (High), indicating a network-exploitable vulnerability with low attack complexity and high impact on availability. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
1.14.6CPE matchmatch criteria
cpe:2.3:a:envoyproxy:envoy:1.14.6:*:*:*:*:*:*:*
1.15.3CPE matchmatch criteria
cpe:2.3:a:envoyproxy:envoy:1.15.3:*:*:*:*:*:*:*
1.16.2CPE matchmatch criteria
cpe:2.3:a:envoyproxy:envoy:1.16.2:*:*:*:*:*:*:*
1.17.1CPE matchmatch criteria
cpe:2.3:a:envoyproxy:envoy:1.17.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.04%
Probability of exploitation in next 30 days
EPSS Percentile
79.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0204 is in the 63rd percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (5)

denopatch availablevia llm_extracted
View patch
invoiceplanepatch availablevia llm_extracted
View patch
pjsippatch availablevia llm_extracted
View patch
redhatpatch availablevia redhat_api
Product: OpenShift Service Mesh 1.1Fixed in: servicemesh-proxy-0:1.1.13-1.el8
View patch
redhatpatch availablevia redhat_api
Product: OpenShift Service Mesh 2.0Fixed in: servicemesh-proxy-0:2.0.3-1.el8
View patch

Vendor Advisories (4)

redhatCVE-2021-28682Important

envoyproxy/envoy: integer overflow handling large grpc-timeouts

Apr 15, 2021
pjsipllm-pjsip-f8dbc0aa2bf38987MEDIUM

Envoy and Istio Denial of Service Vulnerabilities

Jan 1, 2021
invoiceplanellm-invoiceplane-cd13eaa84ec82da5MEDIUM

The Envoy and Istio projects recently announced several new security vulnerabilities (CVE-2021-28683, CVE-2021-28682 and CVE-2021-29258), that could allow an attacker to crash Envoy.

denollm-deno-0e42f54dcae12931MEDIUM

Envoy and Istio Denial of Service Vulnerabilities

References

blog.envoyproxy.io
Vendor Advisory
github.com / envoyproxy/envoy/blob/15e3b9dbcc9aaa9d391fa8033904aad1ea1ae70d/api/envoy/api/v2/cluster.proto
ExploitThird Party Advisory
github.com / envoyproxy/envoy/releases
Third Party Advisory
github.com / envoyproxy/envoy/security/advisories/GHSA-r22g-5f3x-xjgg
Third Party Advisory