CVE-2021-32677: FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints

Q: How do I fix CVE-2021-32677?

fastapi: upgrade to 0.65.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2021-32677 being exploited?

CVE-2021-32677 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-32677 affect?

CVE-2021-32677 affects fastapi, fedora. Severity is high (CVSS 8.2). FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints. FastAPI versions lower than 0.65.2 that used cookies for authentication in path operations that received JSON payloads sent by browsers were

Q: How urgent is CVE-2021-32677?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 8.2REMOTEUPGRADEMITIGATE

CVE-2021-32677 is a high-severity flaw (CVSS 8.2) affecting fastapi, fedora. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints. FastAPI versions lower than 0.65.2 that used cookies for authentication in path operations that received JSON payloads sent by browsers were vulnerable to a Cross-Site Request Forgery (CSRF) attack. In versions lower than 0.65.2, FastAPI would try to read the request payload as JSON even if the content-type header sent was not set to application/jso

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.2 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.7% (top 46%)
CISA exploited list	No
Weakness	CWE-352
Published	2021-06-09
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: fedoraproject · tiangolo

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-06-09 18:15 UTCPublished CVE record published
2026-06-17 03:53 UTCUpdated Record last modified

tiangolo fastapi UPGRADE

Affected: < 0.65.2

Fixed in: 0.65.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy fastapi || rpm -q fastapi || fastapi --version

2. UPGRADE to 0.65.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade fastapi

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade fastapi

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

fedoraproject fedora MITIGATE

Affected: 34

Fixed in: no fixed release known

Safe to downgrade to: a release before 34

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-32677?

fastapi: upgrade to 0.65.2; fedora: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-32677 being exploited?

CVE-2021-32677 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-32677 affect?

CVE-2021-32677 affects fastapi, fedora. Severity is high (CVSS 8.2). FastAPI is a web framework for building APIs with Python 3.6+ based on standard Python type hints. FastAPI versions lower than 0.65.2 that used cookies for authentication in path operations that received JSON payloads sent by browsers were

How urgent is CVE-2021-32677?

Priority 47/100. High severity; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities · FastAPI vulnerabilities

References

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