CVE-2021-22555

mediumpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.787 · 100 %ileexploit · weaponizedDEEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV · 15 exploits · weaponized

Likely / severe?

78.7% (100th) EPSS

CVSS 4.6 · medium

Is it mine?

49 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · osv

added 2025-10-06remediate by 2025-10-27

required action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

EPSS · scored 2026-10-27

Linux Kernel Heap Out-of-Bounds Write Vulnerability

A heap out-of-bounds write affecting Linux since v2.6.19-rc1 was discovered in net/netfilter/x_tables.c. This allows an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space

cvss

Technical severity, 0–10. One row per scoring source.

8.3

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.6–8.3

v2.04.6mediumAV:L/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 3.9 · impact 6.4

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 1.8 · impact 5.9

v3.17.8highAV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.18.3highCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · ENISA EU

v3.18.3highCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:Hsecondary · cve-coordination@google.comexploitability 1.6 · impact 6

v3.17.8highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-787USprimaryCWE-787US

exploits (15)

Public proof-of-concept and weaponised exploit code.

exploit/linux/local/netfilter_xtables_heap_oob_write_priv_escNetfilter x_tables Heap OOB Write Privilege Escalationweaponized · metasploit
EDB-50135Linux Kernel 2.6.19 < 5.9 - 'Netfilter Local Privilege Escalationfunctional · exploit_db
JoneyJunior/cve-2021-22555JoneyJunior/cve-2021-22555PoC · poc_in_github
Spydomain/CVE-2021-22555-PocSpydomain/CVE-2021-22555-PocPoC · poc_in_github
WhatsWrongAndWhy/CVE-2021-22555WhatsWrongAndWhy/CVE-2021-22555PoC · poc_in_github
cgwalters/container-cve-2021-22555cgwalters/container-cve-2021-22555PoC · poc_in_github

affected products (49)

Products and version ranges known to be affected.

IBM InfoSphere Information Serverall versionscert_bundDEcpe:/a:ibm:infosphere_information_server:-
IBM QRadar SIEM 7.3all versionscert_bundDEcpe:/a:ibm:qradar_siem:7.3
IBM QRadar SIEM 7.4all versionscert_bundDEcpe:/a:ibm:qradar_siem:7.4
IBM QRadar SIEM 7.5.0all versionscert_bundDEcpe:/a:ibm:qradar_siem:7.5.0
n/a Linux kernel2.6.19-rc1 → unspecifiedenisa_euvdEU
Red Hat Inc. Red Hat Enterprise Linux≤ 8fstec_bduRU
Red Hat Inc. Red Hat Enterprise Linux≤ 7fstec_bduRU
Red Hat Inc. Red Hat Enterprise Virtualization≤ 4fstec_bduRU
ООО "Открытая мобильная платформа" ОС Аврора≤ 4.0.2fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 7.3fstec_bduRU
ООО «РусБИТех-Астра» Astra Linux Special Edition≤ 1.6 «Смоленск»fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 10fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 9fstec_bduRU
Сообщество свободного программного обеспечения Debian GNU/Linux≤ 11fstec_bduRU
Сообщество свободного программного обеспечения Linux4.0 → 4.4.266fstec_bduRU
Сообщество свободного программного обеспечения Linux4.10 → 4.14.230fstec_bduRU
Сообщество свободного программного обеспечения Linux4.15 → 4.19.187fstec_bduRU
Сообщество свободного программного обеспечения Linux4.20 → 5.4.112fstec_bduRU
Сообщество свободного программного обеспечения Linux4.5 → 4.9.266fstec_bduRU
Сообщество свободного программного обеспечения Linux5.11.0 → 5.11.14fstec_bduRU

showing 20 of 49

advisories (5)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2022-0609Linux Kernel: Schwachstelle ermöglicht Erlangen von SystemrechtenDeutsch2021-07-07csaf · cert_bundDE
Ein lokaler Angreifer kann eine Schwachstelle im Linux Kernel ausnutzen, um Systemrechte zu erlangen und einen Denial of Service Zustand herzustellen.
WID-SEC-W-2023-0063Juniper Junos Space: Mehrere SchwachstellenDeutsch2022-01-12csaf · cert_bundDE
Ein Angreifer aus dem angrenzenden Netzwerk oder ein entfernter anonymer, authentisierter oder lokaler Angreifer kann mehrere Schwachstellen in Juniper Junos Space ausnutzen, um Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, einen Denial-of-Service-Zustand auszulösen, beliebigen Code auszuführen und seine Privilegien zu erweitern.
WID-SEC-W-2025-0227IBM QRadar SIEM: Mehrere SchwachstellenDeutsch2021-11-30csaf · cert_bundDE
Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um seine Privilegien zu erweitern, Administratorrechte zu erlangen, beliebigen Programmcode auszuführen, Informationen offenzulegen, Dateien zu manipulieren oder Sicherheitsvorkehrungen zu umgehen.
WID-SEC-W-2026-2442Oracle JD Edwards: Mehrere SchwachstellenDeutsch2026-07-21csaf · cert_bundDE
Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle JD Edwards ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.
PUB-A-1848478092021-10-01vendor · osvUS
In xt_compat_target_from_user of x_tables.c, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv cert_bund NVD CVE.org MITRE

published 2021-07-07modified 2026-06-17

related (16,124)

Related entries.

ID	severity	EPSS	exploitable	published
CVE-2026-86950US	—OT critical	26.2% (98th)	KEV	2026-09-28
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 18.7.11 and iPadOS 18.7.11, iOS 26.7.1 and iPadOS 26.7.1, macOS Sequoia 15.8.1,…
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Out of bounds write in V8 in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security…
CVE-2026-53362US	—OT critical	0.71% (53rd)	KEV	2026-07-04
In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branc…
CVE-2026-53266US	—OT critical	0.93% (61st)	KEV	2026-06-25
In the Linux kernel, the following vulnerability has been resolved: netfilter: bridge: make ebt_snat ARP rewrite writable The ebtables SNAT target keeps the Ethernet source addre…
CVE-2026-11645US	—OT critical	2.44% (84th)	KEV	2026-06-09
Out of bounds read and write in V8 in Google Chrome prior to 149.0.7827.103 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page. (Chromium…

+16119 more

references (82)

External citations — patches, advisories, analysis.

scry

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