CVE-2021-21708

UAF due to php_filter_float() failing

At a glance

Severity: HIGH 8.2
EPSS: EPSS 3.00 % · percentile 87 (2026-10-27)
State: PUBLISHED
Published: 2022-02-27
Updated: 2024-09-17
Assigner: php
NVD status: Modified

Description

In PHP versions 7.4.x below 7.4.28, 8.0.x below 8.0.16, and 8.1.x below 8.1.3, when using filter functions with FILTER_VALIDATE_FLOAT filter and min/max limits, if the filter fails, there is a possibility to trigger use of allocated memory after free, which can result it crashes, and potentially in overwrite of other memory chunks and RCE. This issue affects: code that uses FILTER_VALIDATE_FLOAT with min/max limits.

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 8.2	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L	php
CVSS 3.1	HIGH 8.2	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L	NVD · security@php.net (Secondary)
CVSS 3.1	CRITICAL 9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	NVD · nvd@nist.gov (Primary)
CVSS 2.0	MEDIUM 6.8	AV:N/AC:M/Au:N/C:P/I:P/A:P	NVD · nvd@nist.gov (Primary)

Weaknesses (CWE)

CWE-416

European references

ENISA EUVD · EUVD-2021-8880
GCVE · GCVE-0-2021-21708

CERT-FR advisories

CERTFR-2024-AVI-0341 — Multiples vulnérabilités dans Synacor Zimbra Collaboration · cert.ssi.gouv.fr
CERTFR-2024-AVI-0295 — Multiples vulnérabilités dans les produits Palo Alto Networks · cert.ssi.gouv.fr
CERTFR-2023-AVI-0537 — Multiples vulnérabilités dans les produits Juniper · cert.ssi.gouv.fr
CERTFR-2022-AVI-161 — Multiples vulnérabilités dans PHP · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:php:php:*:*:*:*:*:*:*:* ≥ 7.4.0 < 7.4.28
cpe:2.3:a:php:php:*:*:*:*:*:*:*:* ≥ 8.0.0 < 8.0.16
cpe:2.3:a:php:php:*:*:*:*:*:*:*:* ≥ 8.1.0 < 8.1.3

Affected products

Product	Versions
PHP Group · PHP	affected 7.4.x < 7.4.28 ; affected 8.0.X < 8.0.16 ; affected 8.1.X < 8.1.3

References

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD