CVE-2026-55584: phpsysinfo Authentication Bypass by Spoofing
Vulnerability summary
CVE-2026-55584 is a high (CVSS 7.5) Authentication Bypass by Spoofing vulnerability in phpsysinfo. EPSS estimates a 1.91% chance of exploitation in the next 30 days, higher than 79.4% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 28-08-2026PublishedVulnerability first disclosed.
- 31-08-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
1.91%
Chance of exploitation in the next 30 days
Percentile
79%
Versus all other CVEs
30-day change
-0.51 pp
From 2.42% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundphpSysInfo 3.4.5 - IP Allowlist Bypass
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Debian1 product
- phpsysinfoAll versions (No fix recorded)
Phpsysinfo1 product
- phpsysinfo< 3.4.6
Ubuntu1 product
- phpsysinfoAll versions (No fix recorded)
3 vendors · 3 products
References
6 links- github.com/phpsysinfo/phpsysinfo/commit/019fa2d7e568ea11461adb4bd33da5dc87c4b9abX Refsource MISCREPORT
