7.5High
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.
What this means for your business
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 2% chance of attack attempts being seen in the next 30 days, ranking above 83% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.
Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness
- CWE-290
- Assigned by
- security-advisories@github.com
Dates
- Published
- 2026-08-28
- Last modified
- 2026-09-09
- Sources
- NVD