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IPv6 ACL bypass in FastCGI listen.allowed_clients due to partial address comparison (memcmp 12 bytes)

Type: advisorySource: OSV1 source record

The IPv6 branch of the FastCGI client access check compares only the first 12 bytes of a 16-byte IPv6 address, so listen.allowed_clients matches on a /96 prefix instead of the exact address. An attacker who can source an address sharing the first 96 bits with an allowed one passes the check and reaches the FastCGI endpoint.

Announced Source revision 1
Original source ↗

BIT-libphp-2026-91768

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:BIT-libphp-2026-91768

libphp

Source reference: /affected/0/package/name

Affected versions
Not stated in this record
Fixed versions
8.2.34

Source reference: /affected/0/ranges

8.3.35

Source reference: /affected/0/ranges

8.4.26

Source reference: /affected/0/ranges

8.5.11

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "SEMVER",
        "events": [
          {
            "introduced": "8.2.0"
          },
          {
            "fixed": "8.2.34"
          },
          {
            "introduced": "8.3.0"
          },
          {
            "fixed": "8.3.35"
          },
          {
            "introduced": "8.4.0"
          },
          {
            "fixed": "8.4.26"
          },
          {
            "introduced": "8.5.0"
          },
          {
            "fixed": "8.5.11"
          }
        ]
      }
    ],
    "package": {
      "name": "libphp",
      "purl": "pkg:bitnami/libphp",
      "ecosystem": "Bitnami"
    },
    "severity": [
      {
        "type": "CVSS_V3",
        "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
      }
    ],
    "database_specific": {
      "source": "https://github.com/bitnami/vulndb/tree/main/data/libphp/BIT-libphp-2026-91768.json"
    }
  }
]
Related CVEs
CVE-2026-91768

Source reference: /aliases

Publisher severity

medium

Source reference: /database_specific/severity

Linked CVE context

These ratings describe the referenced vulnerabilities and products. They are not a severity rating for every application using this dependency.

CVE-2026-91768 · Medium

PHP

Event
#59689 · Revision 1
Added to Heist Feed
Publisher date
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