How severe is CVE-2021-28682?

CVE-2021-28682 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-28682 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28682?

CVE-2021-28682 primarily affects Envoyproxy Envoy. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-28682?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-28682 published?

CVE-2021-28682 was published on 2021-05-20 and last updated on 2026-06-17.

CVE-2021-28682

CVE-2021-28682 is a high-severity vulnerability in Envoyproxy Envoy with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (79th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Envoyproxy Envoy
Published: 2021-05-20
Last modified: 2026-06-17

Description

An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable integer overflow in which a very large grpc-timeout value leads to unexpected timeout calculations.

Frequently asked questions

What is CVE-2021-28682?: An issue was discovered in Envoy through 1.71.1. There is a remotely exploitable integer overflow in which a very large grpc-timeout value leads to unexpected timeout calculations.
How severe is CVE-2021-28682?: CVE-2021-28682 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-28682 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (79th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28682?: CVE-2021-28682 primarily affects Envoyproxy Envoy. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-28682?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-28682 published?: CVE-2021-28682 was published on 2021-05-20 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:envoyproxy:envoy:1.14.6:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:1.15.3:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:1.16.2:*:*:*:*:*:*:*
cpe:2.3:a:envoyproxy:envoy:1.17.1:*:*:*:*:*:*:*

More vulnerabilities in Envoyproxy Envoy

CVE-2022-29226 — Critical (CVSS 10.0): Envoy is a cloud-native high-performance proxy. In versions prior to 1.22.1 the OAuth filter implementation does not…
CVE-2019-18802 — Critical (CVSS 9.8): An issue was discovered in Envoy 1.12.0. An untrusted remote client may send an HTTP header (such as Host) with…
CVE-2019-18801 — Critical (CVSS 9.8): An issue was discovered in Envoy 1.12.0. An untrusted remote client may send HTTP/2 requests that write to the heap…
CVE-2020-35470 — High (CVSS 8.8): Envoy before 1.16.1 logs an incorrect downstream address because it considers only the directly connected peer, not the…
CVE-2024-23324 — High (CVSS 8.6): Envoy is a high-performance edge/middle/service proxy. External authentication can be bypassed by downstream…
CVE-2023-35941 — High (CVSS 8.6): Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0,…

All CVEs affecting Envoyproxy Envoy →

Other CWE-190 (Integer Overflow or Wraparound) vulnerabilities

CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-24814 — Critical (CVSS 10.0): Integer Overflow or Wraparound vulnerability in swoole swoole-src (thirdparty/hiredis modules). This vulnerability is…
CVE-2025-64721 — Critical (CVSS 10.0): Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions…
CVE-2015-5108 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2015-5097 — Critical (CVSS 10.0): Integer overflow in Adobe Reader and Acrobat 10.x before 10.1.15 and 11.x before 11.0.12, Acrobat and Acrobat Reader DC…
CVE-2013-2555 — Critical (CVSS 10.0): Integer overflow in Adobe Flash Player before 10.3.183.75 and 11.x before 11.7.700.169 on Windows and Mac OS X, before…

Browse all CWE-190 (Integer Overflow or Wraparound) vulnerabilities →