CVE-2005-1820: zboard.php in Zeroboard version 4.1pl2 to 4.1pl5 allows remote attackers to execute arbitrary PHP code via imp

This month

HIGH 7.5DOWNGRADE

CVE-2005-1820 is a high-severity flaw (CVSS 7.5) affecting zeroboard. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

zboard.php in Zeroboard version 4.1pl2 to 4.1pl5 allows remote attackers to execute arbitrary PHP code via improper quoting when using the preg_replace function.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	2.7% (top 14%)
CISA exploited list	No
Published	2005-06-01
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: zeroboard

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

Am I affected?

Timeline

2005-06-01 04:00 UTCPublished CVE record published
2026-06-16 22:13 UTCUpdated Record last modified

zeroboard zeroboard DOWNGRADE

Affected: 4.1_pl2 · 4.1_pl3 · 4.1_pl4 · 4.1_pl5

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.1_pl2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 4.1_pl2 (Debian / Ubuntu)

apt-cache madison zeroboard sudo apt install zeroboard=<VERSION_BEFORE_4.1_pl2> sudo apt-mark hold zeroboard

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

dnf --showduplicates list zeroboard sudo dnf downgrade zeroboard-<VERSION_BEFORE_4.1_pl2> sudo dnf versionlock add zeroboard

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: ZeroBoard 4.1 - 'preg_replace' Remote Nobody Shell

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-2005-1820?

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

Is CVE-2005-1820 being exploited?

CVE-2005-1820 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-2005-1820 affect?

CVE-2005-1820 affects zeroboard. Severity is high (CVSS 7.5). zboard.php in Zeroboard version 4.1pl2 to 4.1pl5 allows remote attackers to execute arbitrary PHP code via improper quoting when using the preg_replace function.

How urgent is CVE-2005-1820?

Priority 53/100. High severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2009-4834 MEDIUM 6.8 DOWNGRADE lib.php in Zeroboard 4.1 pl7 allows remote attackers to execute arbitrary PHP code via a crafted parameter nam
CVE-2006-3070 MEDIUM 5.0 DOWNGRADE write_ok.php in Zeroboard 4.1 pl8, when installed on Apache with mod_mime, allows remote attackers to bypass r
CVE-2006-1222 MEDIUM 4.3 DOWNGRADE Multiple cross-site scripting (XSS) vulnerabilities in zeroboard 4.1 pl7 allows allow remote attackers to inje
CVE-2005-0495 MEDIUM 4.3 DOWNGRADE Cross-site scripting (XSS) vulnerability in ZeroBoard allows remote attackers to inject arbitrary web script o
CVE-2005-0380 HIGH 7.5 DOWNGRADE Multiple PHP remote file inclusion vulnerabilities in (1) print_category.php, (2) login.php, (3) setup.php, (4

References

← Back to latest CVEs