CVE-2026-55573

Status: DeferredCritical (9.8)—

Severity9.8Critical · CVSS 3.1

Exploitation probability0.60 %higher than 47% of CVEs

Active exploitationNonot in the CISA catalog

Public exploitNot knownno public code found

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.

CVSS

Base score: 9.8
Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.60 %
Percentile among all scored CVEs: 47
Score date: 10/20/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access95 %
Primary impactT1059 Command and Scripting Interpreterexecution85 %

Vector AV:N/PR:N/UI:N y unserialize() sin restricción en install.php; el texto indica ejecución arbitraria de funciones PHP con privilegios del servidor web.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

ATT&CK mitigations that cover these techniques

Privileged Account Management Vulnerability Scanning Restrict Web-Based Content Network Segmentation Limit Software Installation Limit Access to Resource Over Network

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

E107 — E107^AI

CWEs

CWE-502

References

Show 5 references

Raw JSON (NVD)

Show

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          "version": "2.0.3",
          "timestamp": "2026-10-15T15:00:08.038362Z"
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  "published": "2026-10-14T18:17:38.013",
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  "lastModified": "2026-10-16T20:04:29.760",
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}