CVE-2023-3823 Security issue with external entity loading in XML without enabling it

2023-08-1105:42:25

php

www.cve.org

php

xml

security issue

external entity loading

libxml

imagemagick

disclosure

8.6 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

LOW

Availability Impact

LOW

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

9.2 High

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

25.1%

JSON

In PHP versions 8.0.* before 8.0.30, 8.1.* before 8.1.22, and 8.2.* before 8.2.8 various XML functions rely on libxml global state to track configuration variables, like whether external entities are loaded. This state is assumed to be unchanged unless the user explicitly changes it by calling appropriate function. However, since the state is process-global, other modules - such as ImageMagick - may also use this library within the same process, and change that global state for their internal purposes, and leave it in a state where external entities loading is enabled. This can lead to the situation where external XML is parsed with external entities loaded, which can lead to disclosure of any local files accessible to PHP. This vulnerable state may persist in the same process across many requests, until the process is shut down.

CNA Affected

[
  {
    "defaultStatus": "affected",
    "product": "PHP",
    "vendor": "PHP Group",
    "versions": [
      {
        "lessThan": "8.0.30",
        "status": "affected",
        "version": "8.0.*",
        "versionType": "semver"
      },
      {
        "lessThan": "8.1.22",
        "status": "affected",
        "version": "8.1.*",
        "versionType": "semver"
      },
      {
        "lessThan": "8.2.8",
        "status": "affected",
        "version": "8.2.*",
        "versionType": "semver"
      }
    ]
  }
]