What’s Vulnerable › Vulnerabilities

CVE-2021-32566: Specific sequence of HTTP/2 frames can cause ATS to crash

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-30 · updated 2026-06-17
• Weakness: CWE-20

Description

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.

Affected products

• Apache Software Foundation Apache Traffic Server: from 7.0.0 through 7.1.12; from 8.0.0 through 8.1.1; from 9.0.0 through 9.0.1
• Debian Linux: 10.0

References

• https://lists.apache.org/thread.html/ra1a41ff92a70d25bf576d7da2590575e8ff430393a3f4a0c34de4277%40%3Cusers.trafficserver.apache.org%3E
• https://www.debian.org/security/2021/dsa-4957
• https://lists.apache.org/thread.html/ra1a41ff92a70d25bf576d7da2590575e8ff430393a3f4a0c34de4277%40%3Cusers.trafficserver.apache.org%3E
• https://www.debian.org/security/2021/dsa-4957

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