CVE-2026-55584 (CVSS 7.5)

Description

phpSysInfo is a customizable PHP script that displays system information. Prior to 3.4.6, the PSI_ALLOWED access-control check in read_config.php trusts attacker-controlled X-Forwarded-For and Client-IP HTTP headers before REMOTE_ADDR. A remote unauthenticated attacker can supply an allowed address in one of these headers to impersonate a trusted client and access exposed hostname, kernel, CPU, memory, filesystem, and network-interface information. This issue is fixed in version 3.4.6.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS — Exploit Prediction

0.0242

Probability of exploitation

0.83%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-290 CWE-290

References

Other References

https://github.com/phpsysinfo/phpsysinfo/commit/019fa2d7e568ea11461adb4bd33da5dc87c4b9ab https://github.com/phpsysinfo/phpsysinfo/releases/tag/v3.4.6 https://github.com/phpsysinfo/phpsysinfo/security/advisories/GHSA-786w-p5pm-cvgh

Frequently Asked Questions

What is CVE-2026-55584? +

phpSysInfo is a customizable PHP script that displays system information. Prior to 3.4.6, the PSI_ALLOWED access-control check in read_config.php trusts attacker-controlled X-Forwarded-For and Client-IP HTTP headers before REMOTE_ADDR. A remote unauthenticated attacker can supply an allowed address in one of these headers to impersonate a trusted client and access exposed hostname, kernel, CPU, memory, filesystem, and network-interface information. This issue is fixed in version 3.4.6. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-55584? +

CVE-2026-55584 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0242, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-55584? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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