CVE-2021-27200: In WoWonder 3.0.4, remote attackers can take over any account due to the weak cryptographic algorithm in recov

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-27200 is a critical-severity flaw (CVSS 9.8) affecting wowonder. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In WoWonder 3.0.4, remote attackers can take over any account due to the weak cryptographic algorithm in recover.php. The code parameter is easily predicted from the time of day.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.4% (top 11%)
CISA exploited list	No
Weakness	CWE-330
Published	2021-06-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: wowonder

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

Am I affected?

Timeline

2021-06-11 18:15 UTCPublished CVE record published
2026-06-17 03:44 UTCUpdated Record last modified

wowonder wowonder DOWNGRADE

Affected: 3.0.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.4

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.0.4 (Debian / Ubuntu)

apt-cache madison wowonder sudo apt install wowonder=<VERSION_BEFORE_3.0.4> sudo apt-mark hold wowonder

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list wowonder sudo dnf downgrade wowonder-<VERSION_BEFORE_3.0.4> sudo dnf versionlock add wowonder

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-2021-27200?

wowonder: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-27200 being exploited?

CVE-2021-27200 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-2021-27200 affect?

CVE-2021-27200 affects wowonder. Severity is critical (CVSS 9.8). In WoWonder 3.0.4, remote attackers can take over any account due to the weak cryptographic algorithm in recover.php. The code parameter is easily predicted from the time of day.

How urgent is CVE-2021-27200?

Priority 66/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

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References

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