What is CVE-2021-43082?

CVE-2021-43082 is a critical-severity vulnerability in Apache Traffic Server, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2021-11-03.

How severe is CVE-2021-43082?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Apache Traffic Server

CVE-2021-43082

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in the stats-over-http plugin of Apache Traffic Server allows an attacker to overwrite memory. This issue affects Apache Traffic Server 9.1.0.

Vulnerability class: Buffer Overflow

Published 2021-11-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.024 (83.9th percentile), scored 2026-10-22.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 83.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.024 · newest: 0.024 · change: 0.000

Affected products

Apache Traffic Server
Apache Software Foundation Traffic Server — versions 9.1.0

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

lists.apache.org/thread/k01797hyncx53659wr3o72s5cvkc3164 (Patch, Mailing List, Vendor Advisory)

Frequently asked questions

What is CVE-2021-43082?: CVE-2021-43082 is a critical-severity vulnerability in Apache Traffic Server, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2021-11-03.
How severe is CVE-2021-43082?: Critical severity. CVSS v3 base score is 9.8 out of 10.