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.
CVE-2026-55584
HIGHPre-NVD 7.57.5Elevated
EchelonGraph scoreLOW confidence
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 7.5Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(low)
- EG Risk
- 54(Track)EG Risk 54/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation40% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 2%
- EPSS %ILE
- 83%
- KEV
- Not listed
Published
August 28, 2026
Last Modified
August 28, 2026
Advisory Details (3)
Auto-updated Aug 28, 2026🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available
IP allowlist (PSI_ALLOWED) bypass via spoofed X-Forwarded-For / Client-IP headers · Advisory · phpsysinfo/phpsysinfo · GitHub
https://github.com/phpsysinfo/phpsysinfo/security/advisories/GHSA-786w-p5pm-cvghgithub_release Patch Available
phpSysInfo 3.4.6
Patch available: phpsysinfo/phpsysinfo v3.4.6
https://github.com/phpsysinfo/phpsysinfo/releases/tag/v3.4.6github_commit Patch Available
commit 019fa2d7e568 (phpsysinfo/phpsysinfo)
Patch available: phpsysinfo/phpsysinfo v3.4.6 (contains commit 019fa2d7e568)
https://github.com/phpsysinfo/phpsysinfo/commit/019fa2d7e568ea11461adb4bd33da5dc87c4b9abVendor Advisories for CVE-2026-55584(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-28 20:24 UTCEG score recompute
- 2026-08-28 19:10 UTCEG score recompute
Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- Exploit-DBEDB-52648First seen Aug 17, 2026
phpSysInfo 3.4.5 - IP Allowlist Bypass
Open source ↗
Frequently asked(5)
What is CVE-2026-55584?
CVE-2026-55584 is a high vulnerability published on August 28, 2026. phpSysInfo is a customizable PHP script that displays system information. Prior to 3.4.6, the PSIALLOWED access-control check in readconfig.php trusts attacker-controlled X-Forwarded-For and Client-IP HTTP headers before REMOTE_ADDR. A remote unauthenticated attacker can supply an allowed address…
When was CVE-2026-55584 disclosed?
CVE-2026-55584 was first published in the National Vulnerability Database on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55584 actively exploited?
CVE-2026-55584 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 17.1% of all scored CVEs.
What is the CVSS score of CVE-2026-55584?
CVE-2026-55584 has a CVSS v3 base score of 7.5 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-55584?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55584, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-55584
Is Your Infrastructure Affected by CVE-2026-55584?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.