CVE-2009-4623: Multiple PHP remote file inclusion vulnerabilities in Advanced Comment System 1.0 allow remote attackers to ex

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HIGH 7.5DOWNGRADE

CVE-2009-4623 is a high-severity flaw (CVSS 7.5) affecting advanced comment system. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Multiple PHP remote file inclusion vulnerabilities in Advanced Comment System 1.0 allow remote attackers to execute arbitrary PHP code via a URL in the ACS_path parameter to (1) index.php and (2) admin.php in advanced_comment_system/. NOTE: this might only be a vulnerability when the administrator has not followed installation instructions in install.php. NOTE: this might be the same as CVE-2020-35598.

Why this priority

High severity
EPSS top 4%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	9.8% (top 4%)
CISA exploited list	No
Weakness	CWE-94
Published	2010-01-18
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: plohni

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

Am I affected?

Timeline

2010-01-18 20:30 UTCPublished CVE record published
2026-06-16 23:14 UTCUpdated Record last modified

plohni advanced comment system 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 advanced-comment-system || rpm -q advanced-comment-system || advanced-comment-system --version

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

apt-cache madison advanced-comment-system sudo apt install advanced-comment-system=<VERSION_BEFORE_1.0> sudo apt-mark hold advanced-comment-system

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

dnf --showduplicates list advanced-comment-system sudo dnf downgrade advanced-comment-system-<VERSION_BEFORE_1.0> sudo dnf versionlock add advanced-comment-system

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: Advanced Comment System 1.0 - Multiple Remote File Inclusions

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-2009-4623?

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

Is CVE-2009-4623 being exploited?

CVE-2009-4623 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-2009-4623 affect?

CVE-2009-4623 affects advanced comment system. Severity is high (CVSS 7.5). Multiple PHP remote file inclusion vulnerabilities in Advanced Comment System 1.0 allow remote attackers to execute arbitrary PHP code via a URL in the ACS_path parameter to (1) index.php and (2) admin.php in advanced_comment_system/. NOTE:

How urgent is CVE-2009-4623?

Priority 55/100. High severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2020-35598 HIGH 7.5 DOWNGRADE ACS Advanced Comment System 1.0 is affected by Directory Traversal via an advanced_component_system/index.php?
CVE-2018-18845 MEDIUM 6.1 DOWNGRADE internal/advanced_comment_system/index.php and internal/advanced_comment_system/admin.php in Advanced Comment
CVE-2018-18619 CRITICAL 9.8 DOWNGRADE internal/advanced_comment_system/admin.php in Advanced Comment System 1.0 is prone to an SQL injection vulnera

References

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