CVE-2020-35598: ACS Advanced Comment System 1.0 is affected by Directory Traversal via an advanced_component_system/index.php?

This week

HIGH 7.5REMOTEDOWNGRADE

CVE-2020-35598 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.

ACS Advanced Comment System 1.0 is affected by Directory Traversal via an advanced_component_system/index.php?ACS_path=..%2f URI. NOTE: this might be the same as CVE-2009-4623

Why this priority

High severity
EPSS top 2%: very likely to be exploited
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	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	20.8% (top 2%)
CISA exploited list	No
Weakness	CWE-22
Published	2020-12-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: advanced comment system project

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

Am I affected?

Timeline

2020-12-23 19:15 UTCPublished CVE record published
2026-06-17 03:14 UTCUpdated Record last modified

advanced comment system project 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 - 'ACS_path' Path Traversal
Nuclei scan template: Advanced Comment System 1.0 - Local File Inclusion

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-2020-35598?

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

Is CVE-2020-35598 being exploited?

CVE-2020-35598 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-2020-35598 affect?

CVE-2020-35598 affects advanced comment system. Severity is high (CVSS 7.5). ACS Advanced Comment System 1.0 is affected by Directory Traversal via an advanced_component_system/index.php?ACS_path=..%2f URI. NOTE: this might be the same as CVE-2009-4623

How urgent is CVE-2020-35598?

Priority 61/100. High severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

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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