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Vulnerability details: VCID-hhzm-w9z3-aaab
Vulnerability ID VCID-hhzm-w9z3-aaab
Aliases CVE-2021-21703
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-787 Out-of-bounds Write
CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
System Score Found at
generic_textual High http://people.canonical.com/~ubuntu-security/cve/2021/CVE-2021-21703.html
rhas Moderate https://access.redhat.com/errata/RHSA-2022:1935
rhas Important https://access.redhat.com/errata/RHSA-2022:5491
cvssv3 6.4 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-21703.json
epss 0.00057 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00077 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
epss 0.00133 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
epss 0.00133 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00148 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00309 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
epss 0.00309 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
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epss 0.00309 https://api.first.org/data/v1/epss?cve=CVE-2021-21703
rhbs medium https://bugzilla.redhat.com/show_bug.cgi?id=2016535
generic_textual High https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21703
cvssv3.1 6.4 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
generic_textual High https://github.com/php/php-src/commit/fadb1f8c1d08ae62b4f0a16917040fde57a3b93b
cvssv2 6.9 https://nvd.nist.gov/vuln/detail/CVE-2021-21703
cvssv3 7.0 https://nvd.nist.gov/vuln/detail/CVE-2021-21703
cvssv3.1 7.0 https://nvd.nist.gov/vuln/detail/CVE-2021-21703
archlinux Medium https://security.archlinux.org/AVG-2486
generic_textual High https://ubuntu.com/security/notices/USN-5125-1
generic_textual High https://www.ambionics.io/blog/php-fpm-local-root
cvssv3.1 5.3 https://www.oracle.com/security-alerts/cpuapr2022.html
generic_textual MODERATE https://www.oracle.com/security-alerts/cpuapr2022.html
cvssv3.1 6.6 https://www.oracle.com/security-alerts/cpujan2022.html
generic_textual MODERATE https://www.oracle.com/security-alerts/cpujan2022.html
Reference id Reference type URL
http://people.canonical.com/~ubuntu-security/cve/2021/CVE-2021-21703.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-21703.json
https://api.first.org/data/v1/epss?cve=CVE-2021-21703
https://bugs.php.net/bug.php?id=81026
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-21703
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://github.com/php/php-src/commit/fadb1f8c1d08ae62b4f0a16917040fde57a3b93b
https://lists.debian.org/debian-lts-announce/2021/10/msg00021.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6PZVLICZUJMXOGWOUWSBAEGIVTF6Y6V3/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JO5RA6YOBGGGKLIA6F6BQRZDDECF5L3R/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PBM3KKB3RY2YPOKNMC4HIH7IH3T3WC74/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6PZVLICZUJMXOGWOUWSBAEGIVTF6Y6V3/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JO5RA6YOBGGGKLIA6F6BQRZDDECF5L3R/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PBM3KKB3RY2YPOKNMC4HIH7IH3T3WC74/
https://security.gentoo.org/glsa/202209-20
https://security.netapp.com/advisory/ntap-20211118-0003/
https://ubuntu.com/security/notices/USN-5125-1
https://www.ambionics.io/blog/php-fpm-local-root
https://www.debian.org/security/2021/dsa-4992
https://www.debian.org/security/2021/dsa-4993
https://www.oracle.com/security-alerts/cpuapr2022.html
https://www.oracle.com/security-alerts/cpujan2022.html
http://www.openwall.com/lists/oss-security/2021/10/26/7
2016535 https://bugzilla.redhat.com/show_bug.cgi?id=2016535
997003 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=997003
AVG-2486 https://security.archlinux.org/AVG-2486
cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*
cpe:2.3:a:oracle:communications_diameter_signaling_router:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:communications_diameter_signaling_router:*:*:*:*:*:*:*:*
cpe:2.3:a:php:php:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
CVE-2021-21703 https://nvd.nist.gov/vuln/detail/CVE-2021-21703
RHSA-2022:1935 https://access.redhat.com/errata/RHSA-2022:1935
RHSA-2022:5491 https://access.redhat.com/errata/RHSA-2022:5491
USN-5125-1 https://usn.ubuntu.com/5125-1/
No exploits are available.
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-21703.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:L/AC:M/Au:N/C:C/I:C/A:C Found at https://nvd.nist.gov/vuln/detail/CVE-2021-21703
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-21703
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-21703
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N Found at https://www.oracle.com/security-alerts/cpuapr2022.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H Found at https://www.oracle.com/security-alerts/cpujan2022.html
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.14574
EPSS Score 0.00057
Published At March 28, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
There are no relevant records.