What is CVE-2021-33194?

CVE-2021-33194 is a high-severity vulnerability in Golang Go, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-05-26.

How severe is CVE-2021-33194?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-33194 known to be exploited?

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

Vulnerability in Golang Go

CVE-2021-33194

golang.org/x/net before v0.0.0-20210520170846-37e1c6afe023 allows attackers to cause a denial of service (infinite loop) via crafted ParseFragment input.

Published 2021-05-26 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.075 (94.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 94.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.075 · newest: 0.075 · change: 0.000

Affected products

Golang Go
Fedoraproject Fedora — versions 36

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

Public proof-of-concept exploits

References

groups.google.com/g/golang-announce/c/wPunbCPkWUg (Third Party Advisory)
github.com/golang/net/commit/37e1c6afe02340126705deced573a85ab75209d7 (Patch, Third Party Advisory)
lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)

Frequently asked questions

What is CVE-2021-33194?: CVE-2021-33194 is a high-severity vulnerability in Golang Go, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 7.5/10. Published 2021-05-26.
How severe is CVE-2021-33194?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-33194 known to be exploited?: 8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.