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CVE-2026-55573: e107 install page lets attacker run code on server

CVE-2026-55573 · published 4 days ago

Summary

Versions of the e107 website system older than 2.3.7 leave the install.php script reachable after a normal setup. An attacker who can send a specially crafted request to that script can cause the web server to execute any code, effectively taking full control of the server. Update to version 2.3.7 or later and restrict or delete the installer file after installation.

What to do

The CVE record does not list a fixed version. Check the vendor's site or the advisory links below - a fix may already be released.

Affected software

Vendor	Product	Affected versions
e107inc	e107	< 2.3.7

Original advisory text

e107: Unsafe deserialization in install.php allows unauthenticated RCE via POP chain

e107 is a content management system (CMS). Prior to 2.3.7, install.php decodes the attacker-controlled previous_steps POST parameter and passes it to unserialize() at file scope and again in the e_install constructor without restricting allowed classes. The installer remains accessible after a normal installation, and a crafted object graph using the bundled GuzzleHttp\Psr7\PumpStream class can flow through paths.hash into site_path, where string coercion invokes an attacker-controlled callable. An unauthenticated attacker who can reach install.php can therefore execute arbitrary PHP functions with the web server process's privileges, leading to full server compromise. This issue is fixed in version 2.3.7.

References

https://github.com/e107inc/e107/commit/5d6d649e8cf01854d6024d07997c2449fdd75f24 Patch
https://github.com/e107inc/e107/commit/6c404295213952aedb9b3689be19dd4c7ba550b0 Patch
https://github.com/e107inc/e107/releases/tag/v2.3.7 URL
https://github.com/e107inc/e107/security/advisories/GHSA-c8h6-wpj3-4cr8 Vendor Advisory
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55573... Vendor Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-55573 Vendor Advisory

Fix within

Internet-facing 3 days

Internal 60 days

Not known to be exploited
Can be exploited automatically
Gives an attacker full control

Severity

9.8 Critical

Exploitation

<1% chance of attack within 30 days

Type

CWE-502Deserialization of Untrusted Data

Timeline

Published14 Oct 2026

Updated17 Oct 2026

First seen14 Oct 2026

Sources

CVE-2026-55573 · NVD

CVE-2026-55573 · MITRE

CVE-2026-55573 · OSV

GHSA-c8h6-wpj3-4cr8 · GHSA

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