CVE-2002-0491: admin.php in AlGuest 1.0 guestbook checks for the existence of the admin cookie to authenticate the AlGuest ad

This week

HIGH 10.0DOWNGRADE

CVE-2002-0491 is a high-severity flaw (CVSS 10.0) affecting alguest. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

admin.php in AlGuest 1.0 guestbook checks for the existence of the admin cookie to authenticate the AlGuest administrator, which allows remote attackers to bypass the authentication and gain privileges by setting the admin cookie to an arbitrary value.

Why this priority

Critical severity
Public exploit reference

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

Risk facts

CVSS score	10.0 (High)
EPSS exploit chance	3.2% (top 12%)
CISA exploited list	No
Published	2002-08-12
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: alguest

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2002-08-12 04:00 UTCPublished CVE record published
2026-06-16 21:57 UTCUpdated Record last modified

alguest alguest DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison alguest sudo apt install alguest=<VERSION_BEFORE_1.0> sudo apt-mark hold alguest

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

dnf --showduplicates list alguest sudo dnf downgrade alguest-<VERSION_BEFORE_1.0> sudo dnf versionlock add alguest

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-2002-0491?

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

Is CVE-2002-0491 being exploited?

CVE-2002-0491 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-2002-0491 affect?

CVE-2002-0491 affects alguest. Severity is high (CVSS 10.0). admin.php in AlGuest 1.0 guestbook checks for the existence of the admin cookie to authenticate the AlGuest administrator, which allows remote attackers to bypass the authentication and gain privileges by setting the admin cookie to an arbi

How urgent is CVE-2002-0491?

Priority 62/100. Critical severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2010-4407 MEDIUM 4.3 DOWNGRADE Multiple cross-site scripting (XSS) vulnerabilities in index.php in AlGuest 1.1c-patched allow remote attacker

References

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