CVE-2020-7245: Incorrect username validation in the registration process of CTFd v2.0.0 - v2.2.2 allows an attacker to take o

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CRITICAL 9.8REMOTEUPGRADE

CVE-2020-7245 is a critical-severity flaw (CVSS 9.8) affecting ctfd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Incorrect username validation in the registration process of CTFd v2.0.0 - v2.2.2 allows an attacker to take over an arbitrary account if the username is known and emails are enabled on the CTFd instance. To exploit the vulnerability, one must register with a username identical to the victim's username, but with white space inserted before and/or after the username. This will register the account with the same username as the victim. After initia

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 33%)
CISA exploited list	No
Weakness	CWE-640
Published	2020-01-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: ctfd

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

Am I affected?

Timeline

2020-01-23 23:15 UTCPublished CVE record published
2026-06-17 03:24 UTCUpdated Record last modified

ctfd ctfd UPGRADE

Affected: >= 2.0.0 and <= 2.2.2

Fixed in: newer than 2.2.2

Safe to downgrade to: a release before 2.0.0

1. Check installed version

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

2. UPGRADE to newer than 2.2.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ctfd

Note

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

3. If no update is available yet, DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison ctfd sudo apt install ctfd=<VERSION_BEFORE_2.0.0> sudo apt-mark hold ctfd

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list ctfd sudo dnf downgrade ctfd-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add ctfd

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2020-7245?

ctfd: upgrade to newer than 2.2.2. Exact commands for each OS are on this page.

Is CVE-2020-7245 being exploited?

CVE-2020-7245 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-2020-7245 affect?

CVE-2020-7245 affects ctfd. Severity is critical (CVSS 9.8). Incorrect username validation in the registration process of CTFd v2.0.0 - v2.2.2 allows an attacker to take over an arbitrary account if the username is known and emails are enabled on the CTFd instance. To exploit the vulnerability, one m

How urgent is CVE-2020-7245?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

References

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