CVE-2021-32566

What it is

Improper Input Validation vulnerability in HTTP/2 of Apache Traffic Server allows an attacker to DOS the server. This issue affects Apache Traffic Server 7.0.0 to 7.1.12, 8.0.0 to 8.1.1, 9.0.0 to 9.0.1.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

2.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-06-30 08:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:53 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.4% in the next 30 days (EPSS).
• Severity: 7.5 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-06-30 08:15 UTC

Last modified

2026-06-17 03:53 UTC

Exploit probability

2.4% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Apache Traffic Server ≤ 7.1.12
• Apache Traffic Server ≤ 8.1.1
• Apache Traffic Server ≤ 9.0.1
• Debian Linux 10.0

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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