What is CVE-2021-36161?

CVE-2021-36161 is a critical-severity vulnerability in Apache Dubbo, classified under Use of Externally-Controlled Format String. CVSS score: 9.8/10. Published 2021-09-09.

How severe is CVE-2021-36161?

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

Is CVE-2021-36161 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Apache Dubbo

CVE-2021-36161

Some component in Dubbo will try to print the formated string of the input arguments, which will possibly cause RCE for a maliciously customized bean with special toString method. In the latest version, we fix the toString call in timeout, cache and some other places. Fixed in Apache Dubbo 2.7.13

Published 2021-09-09 · 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: 0.025 (83.9th percentile), scored 2026-10-01.

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: 0.025 · newest: 0.025 · change: 0.000

Affected products

Apache Dubbo
Apache Software Foundation Dubbo — versions Apache Dubbo 2.7.x

Weakness classification (CWE)

CWE-134 — Use of Externally-Controlled Format String

Public proof-of-concept exploits

References

lists.apache.org/thread.html/r40212261fd5d638074b65f22ac73eebe93ace310c79d4cfcc… (Mailing List, Vendor Advisory)

Frequently asked questions

What is CVE-2021-36161?: CVE-2021-36161 is a critical-severity vulnerability in Apache Dubbo, classified under Use of Externally-Controlled Format String. CVSS score: 9.8/10. Published 2021-09-09.
How severe is CVE-2021-36161?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-36161 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.