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cvelistPhpCVELIST:CVE-2021-21703
HistoryOct 18, 2021 - 12:00 a.m.

CVE-2021-21703 PHP-FPM memory access in root process leading to privilege escalation

2021-10-1800:00:00
CWE-284
CWE-787
php
www.cve.org
4

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

AI Score

7.7

Confidence

High

EPSS

0.001

Percentile

51.0%

In PHP versions 7.3.x up to and including 7.3.31, 7.4.x below 7.4.25 and 8.0.x below 8.0.12, when running PHP FPM SAPI with main FPM daemon process running as root and child worker processes running as lower-privileged users, it is possible for the child processes to access memory shared with the main process and write to it, modifying it in a way that would cause the root process to conduct invalid memory reads and writes, which can be used to escalate privileges from local unprivileged user to the root user.

CNA Affected

[
  {
    "product": "PHP",
    "vendor": "PHP Group",
    "versions": [
      {
        "lessThanOrEqual": "7.3.31",
        "status": "affected",
        "version": "7.3.x",
        "versionType": "custom"
      },
      {
        "lessThan": "7.4.25",
        "status": "affected",
        "version": "7.4.x",
        "versionType": "custom"
      },
      {
        "lessThan": "8.0.12",
        "status": "affected",
        "version": "8.0.X",
        "versionType": "custom"
      }
    ]
  }
]

CVSS3

7.8

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

AI Score

7.7

Confidence

High

EPSS

0.001

Percentile

51.0%