CVE-2021-31525

Name: CVE-2021-31525
Creator: NVD / NIST
Published: 2021-05-27T13:15:08.207+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 3.69%

Last modified Jun 17, 2026

CVE-2021-31525 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. net/http in Go before 1.15.12 and 1.16.x before 1.16.4 allows remote attackers to cause a denial of service (panic) via a large header to ReadRequest or ReadResponse. Server, Transport, and Client can each be affected in some configurations.. EPSS estimates a 3.69% chance of exploitation in the next 30 days.

Description

net/http in Go before 1.15.12 and 1.16.x before 1.16.4 allows remote attackers to cause a denial of service (panic) via a large header to ReadRequest or ReadResponse. Server, Transport, and Client can each be affected in some configurations.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

3.69%

88.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-674

Affected Software

Vendor	Product	Versions
Golang	Go	< 1.15.12
Golang	Go	>= 1.16.0, < 1.16.4
Fedoraproject	Fedora	34

References

https://github.com/golang/go/issues/45710Issue Tracking, Patch, Third Party Advisory
https://groups.google.com/g/golang-announce/c/cu9SP4eSXMcMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ISRZZ6NY5R2TBYE72KZFOCO25TEUQTBF/
https://security.gentoo.org/glsa/202208-02Third Party Advisory
https://github.com/golang/go/issues/45710Issue Tracking, Patch, Third Party Advisory
https://groups.google.com/g/golang-announce/c/cu9SP4eSXMcMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ISRZZ6NY5R2TBYE72KZFOCO25TEUQTBF/
https://security.gentoo.org/glsa/202208-02Third Party Advisory

Timeline

Published: May 27, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-31525?

How severe is CVE-2021-31525?

CVE-2021-31525 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 3.69% probability of exploitation in the next 30 days.

How do I fix CVE-2021-31525?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-31525?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST