CVE-2020-18121: A configuration issue in Indexhibit 2.1.5 allows authenticated attackers to modify .php files, leading to gets

This month

HIGH 8.8DOWNGRADE

CVE-2020-18121 is a high-severity flaw (CVSS 8.8) affecting indexhibit. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A configuration issue in Indexhibit 2.1.5 allows authenticated attackers to modify .php files, leading to getshell.

Why this priority

High severity
Public exploit reference

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

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Weakness	CWE-732
Published	2021-08-30
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: indexhibit

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

Am I affected?

Timeline

2021-08-30 18:15 UTCPublished CVE record published
2026-06-17 02:59 UTCUpdated Record last modified

indexhibit indexhibit DOWNGRADE

Affected: 2.1.5

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.5

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1.5 (Debian / Ubuntu)

apt-cache madison indexhibit sudo apt install indexhibit=<VERSION_BEFORE_2.1.5> sudo apt-mark hold indexhibit

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

dnf --showduplicates list indexhibit sudo dnf downgrade indexhibit-<VERSION_BEFORE_2.1.5> sudo dnf versionlock add indexhibit

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-2020-18121?

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

Is CVE-2020-18121 being exploited?

CVE-2020-18121 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-2020-18121 affect?

CVE-2020-18121 affects indexhibit. Severity is high (CVSS 8.8). A configuration issue in Indexhibit 2.1.5 allows authenticated attackers to modify .php files, leading to getshell.

How urgent is CVE-2020-18121?

Priority 51/100. High severity; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2020-18127 MEDIUM 6.5 DOWNGRADE An issue in the /config/config.php component of Indexhibit 2.1.5 allows attackers to arbitrarily view files.
CVE-2020-18126 MEDIUM 5.4 DOWNGRADE Multiple stored cross-site scripting (XSS) vulnerabilities in the Sections module of Indexhibit 2.1.5 allows a
CVE-2020-18125 MEDIUM 6.1 DOWNGRADE A reflected cross-site scripting (XSS) vulnerability in the /plugin/ajax.php component of Indexhibit 2.1.5 all
CVE-2020-18124 MEDIUM 5.7 DOWNGRADE A cross-site request forgery (CSRF) vulnerability in Indexhibit 2.1.5 allows attackers to arbitrarily reset ac
CVE-2020-18123 MEDIUM 6.5 DOWNGRADE A cross-site request forgery (CSRF) vulnerability in Indexhibit 2.1.5 allows attackers to arbitrarily delete a

References

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