Vulnerability-Lookup

BDU:2025-04360 (CVE-2021-47546)

Vulnerability from fstec – Published: 2025-04-14 – Updated: 2025-04-14 – View on bdu.fstec.ru Fixed

Title

Уязвимость функции fib4_rule_action() модуля net/ipv4/fib_rules.c реализации протокола IPv4 ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании

Summary

Уязвимость функции fib4_rule_action() модуля net/ipv4/fib_rules.c реализации протокола IPv4 ядра операционной системы Linux связана с неправильным освобождением памяти перед удалением последней ссылки («утечка памяти»). Эксплуатация уязвимости может позволить нарушителю вызвать отказ в обслуживании

Severity

4.6 (Medium) CVSS 2.0


                      
                        AV:L/AC:L/Au:S/C:N/I:N/A:C

5.5 (Medium) CVSS 3.0


                      
                        CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Class

Code vulnerability

Status

Confirmed by the vendor

Exploitation

Resource exhaustion

Incidents

Being clarified

Remediation

Software update

CWE

CWE-401 - Неправильное освобождение памяти перед удалением последней ссылки («утечка памяти»)

Aliases

CVE-2021-47546

References

12 references

URL
https://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa
https://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383
https://git.kernel.org/stable/c/ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29
https://www.cve.org/CVERecord?id=CVE-2021-47546
https://lore.kernel.org/linux-cve-announce/2024052440-CVE-2021-47546-f25b@gregkh/
https://git.kernel.org/linus/cdef485217d30382f3bf6448c54b4401648fe3f1
https://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commi…
https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.164
https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.84
https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.7
https://security-tracker.debian.org/tracker/CVE-2021-47546
https://ubuntu.com/security/CVE-2021-47546

Impacted products

3 products from 2 vendors

Vendors

Canonical Ltd., Сообщество свободного программного обеспечения

Products

Ubuntu, Debian GNU/Linux, Linux

Versions

18.04 LTS (Ubuntu), 20.04 LTS (Ubuntu), 11 (Debian GNU/Linux), 12 (Debian GNU/Linux), 22.04 LTS (Ubuntu), от 5.5 до 5.10.83 включительно (Linux), от 5.11 до 5.15.6 включительно (Linux), от 5.2.19 до 5.3 (Linux), от 5.3.4 до 5.4.163 включительно (Linux)

Product types

Operating system

Platforms

Canonical Ltd. Ubuntu 18.04 LTS, Canonical Ltd. Ubuntu 20.04 LTS, Сообщество свободного программного обеспечения Debian GNU/Linux 11, Сообщество свободного программного обеспечения Debian GNU/Linux 12, Canonical Ltd. Ubuntu 22.04 LTS, Сообщество свободного программного обеспечения Linux от 5.5 до 5.10.83 включительно, Сообщество свободного программного обеспечения Linux от 5.11 до 5.15.6 включительно, Сообщество свободного программного обеспечения Linux от 5.2.19 до 5.3, Сообщество свободного программного обеспечения Linux от 5.3.4 до 5.4.163 включительно

Mitigations

В условиях отсутствия обновлений безопасности от производителя рекомендуется придерживаться "Рекомендаций по безопасной настройке операционных систем LINUX", изложенных в методическом документе ФСТЭК России, утверждённом 25 декабря 2022 года. Использование рекомендаций: Для Linux: https://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa https://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 https://git.kernel.org/stable/c/ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29 https://lore.kernel.org/linux-cve-announce/2024052440-CVE-2021-47546-f25b@gregkh/ https://git.kernel.org/linus/cdef485217d30382f3bf6448c54b4401648fe3f1 https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.164 https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.84 https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.7 Для Debian GNU/Linux: https://security-tracker.debian.org/tracker/CVE-2021-47546 Для Ubuntu: https://ubuntu.com/security/CVE-2021-47546

JSON

To clipboard

{
  "CVSS 2.0": "AV:L/AC:L/Au:S/C:N/I:N/A:C",
  "CVSS 3.0": "AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
  "CVSS 4.0": null,
  "remediation_\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": null,
  "remediation_\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435": null,
  "\u0412\u0435\u043d\u0434\u043e\u0440 \u041f\u041e": "Canonical Ltd., \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0412\u0435\u0440\u0441\u0438\u044f \u041f\u041e": "18.04 LTS (Ubuntu), 20.04 LTS (Ubuntu), 11 (Debian GNU/Linux), 12 (Debian GNU/Linux), 22.04 LTS (Ubuntu), \u043e\u0442 5.5 \u0434\u043e 5.10.83 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 5.11 \u0434\u043e 5.15.6 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux), \u043e\u0442 5.2.19 \u0434\u043e 5.3 (Linux), \u043e\u0442 5.3.4 \u0434\u043e 5.4.163 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e (Linux)",
  "\u0412\u043e\u0437\u043c\u043e\u0436\u043d\u044b\u0435 \u043c\u0435\u0440\u044b \u043f\u043e \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044e": "\u0412 \u0443\u0441\u043b\u043e\u0432\u0438\u044f\u0445 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u044f \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0439 \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u043e\u0442 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u044f \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0443\u0435\u0442\u0441\u044f \u043f\u0440\u0438\u0434\u0435\u0440\u0436\u0438\u0432\u0430\u0442\u044c\u0441\u044f \"\u0420\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439 \u043f\u043e \u0431\u0435\u0437\u043e\u043f\u0430\u0441\u043d\u043e\u0439 \u043d\u0430\u0441\u0442\u0440\u043e\u0439\u043a\u0435 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u044b\u0445 \u0441\u0438\u0441\u0442\u0435\u043c LINUX\", \u0438\u0437\u043b\u043e\u0436\u0435\u043d\u043d\u044b\u0445 \u0432 \u043c\u0435\u0442\u043e\u0434\u0438\u0447\u0435\u0441\u043a\u043e\u043c \u0434\u043e\u043a\u0443\u043c\u0435\u043d\u0442\u0435 \u0424\u0421\u0422\u042d\u041a \u0420\u043e\u0441\u0441\u0438\u0438, \u0443\u0442\u0432\u0435\u0440\u0436\u0434\u0451\u043d\u043d\u043e\u043c 25 \u0434\u0435\u043a\u0430\u0431\u0440\u044f 2022 \u0433\u043e\u0434\u0430.\n\n\u0418\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0435 \u0440\u0435\u043a\u043e\u043c\u0435\u043d\u0434\u0430\u0446\u0438\u0439:\n\u0414\u043b\u044f Linux:\nhttps://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa\nhttps://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383\nhttps://git.kernel.org/stable/c/ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29\nhttps://lore.kernel.org/linux-cve-announce/2024052440-CVE-2021-47546-f25b@gregkh/\nhttps://git.kernel.org/linus/cdef485217d30382f3bf6448c54b4401648fe3f1\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.164\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.84\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.7\n\n\u0414\u043b\u044f Debian GNU/Linux:\nhttps://security-tracker.debian.org/tracker/CVE-2021-47546\n\n\u0414\u043b\u044f Ubuntu:\nhttps://ubuntu.com/security/CVE-2021-47546",
  "\u0414\u0430\u0442\u0430 \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0438\u044f": "23.11.2021",
  "\u0414\u0430\u0442\u0430 \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0433\u043e \u043e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u044f": "14.04.2025",
  "\u0414\u0430\u0442\u0430 \u043f\u0443\u0431\u043b\u0438\u043a\u0430\u0446\u0438\u0438": "14.04.2025",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440": "BDU:2025-04360",
  "\u0418\u0434\u0435\u043d\u0442\u0438\u0444\u0438\u043a\u0430\u0442\u043e\u0440\u044b \u0434\u0440\u0443\u0433\u0438\u0445 \u0441\u0438\u0441\u0442\u0435\u043c \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0439 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "CVE-2021-47546",
  "\u0418\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f \u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0430",
  "\u041a\u043b\u0430\u0441\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u043a\u043e\u0434\u0430",
  "\u041d\u0430\u0437\u0432\u0430\u043d\u0438\u0435 \u041f\u041e": "Ubuntu, Debian GNU/Linux, Linux",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u041e\u0421 \u0438 \u0442\u0438\u043f \u0430\u043f\u043f\u0430\u0440\u0430\u0442\u043d\u043e\u0439 \u043f\u043b\u0430\u0442\u0444\u043e\u0440\u043c\u044b": "Canonical Ltd. Ubuntu 18.04 LTS , Canonical Ltd. Ubuntu 20.04 LTS , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 11 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Debian GNU/Linux 12 , Canonical Ltd. Ubuntu 22.04 LTS , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 5.5 \u0434\u043e 5.10.83 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 5.11 \u0434\u043e 5.15.6 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 5.2.19 \u0434\u043e 5.3 , \u0421\u043e\u043e\u0431\u0449\u0435\u0441\u0442\u0432\u043e \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e\u0433\u043e \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f Linux \u043e\u0442 5.3.4 \u0434\u043e 5.4.163 \u0432\u043a\u043b\u044e\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e ",
  "\u041d\u0430\u0438\u043c\u0435\u043d\u043e\u0432\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 fib4_rule_action() \u043c\u043e\u0434\u0443\u043b\u044f net/ipv4/fib_rules.c \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 IPv4 \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438",
  "\u041d\u0430\u043b\u0438\u0447\u0438\u0435 \u044d\u043a\u0441\u043f\u043b\u043e\u0439\u0442\u0430": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "\u041d\u0435\u043f\u0440\u0430\u0432\u0438\u043b\u044c\u043d\u043e\u0435 \u043e\u0441\u0432\u043e\u0431\u043e\u0436\u0434\u0435\u043d\u0438\u0435 \u043f\u0430\u043c\u044f\u0442\u0438 \u043f\u0435\u0440\u0435\u0434 \u0443\u0434\u0430\u043b\u0435\u043d\u0438\u0435\u043c \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0439 \u0441\u0441\u044b\u043b\u043a\u0438 (\u00ab\u0443\u0442\u0435\u0447\u043a\u0430 \u043f\u0430\u043c\u044f\u0442\u0438\u00bb) (CWE-401)",
  "\u041e\u043f\u0438\u0441\u0430\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0423\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c \u0444\u0443\u043d\u043a\u0446\u0438\u0438 fib4_rule_action() \u043c\u043e\u0434\u0443\u043b\u044f net/ipv4/fib_rules.c \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u043f\u0440\u043e\u0442\u043e\u043a\u043e\u043b\u0430 IPv4 \u044f\u0434\u0440\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u043e\u0439 \u0441\u0438\u0441\u0442\u0435\u043c\u044b Linux \u0441\u0432\u044f\u0437\u0430\u043d\u0430 \u0441 \u043d\u0435\u043f\u0440\u0430\u0432\u0438\u043b\u044c\u043d\u044b\u043c \u043e\u0441\u0432\u043e\u0431\u043e\u0436\u0434\u0435\u043d\u0438\u0435\u043c \u043f\u0430\u043c\u044f\u0442\u0438 \u043f\u0435\u0440\u0435\u0434 \u0443\u0434\u0430\u043b\u0435\u043d\u0438\u0435\u043c \u043f\u043e\u0441\u043b\u0435\u0434\u043d\u0435\u0439 \u0441\u0441\u044b\u043b\u043a\u0438 (\u00ab\u0443\u0442\u0435\u0447\u043a\u0430 \u043f\u0430\u043c\u044f\u0442\u0438\u00bb). \u042d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442 \u043f\u043e\u0437\u0432\u043e\u043b\u0438\u0442\u044c \u043d\u0430\u0440\u0443\u0448\u0438\u0442\u0435\u043b\u044e \u0432\u044b\u0437\u0432\u0430\u0442\u044c \u043e\u0442\u043a\u0430\u0437 \u0432 \u043e\u0431\u0441\u043b\u0443\u0436\u0438\u0432\u0430\u043d\u0438\u0438",
  "\u041f\u043e\u0441\u043b\u0435\u0434\u0441\u0442\u0432\u0438\u044f \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": null,
  "\u041f\u0440\u043e\u0447\u0430\u044f \u0438\u043d\u0444\u043e\u0440\u043c\u0430\u0446\u0438\u044f": null,
  "\u0421\u0432\u044f\u0437\u044c \u0441 \u0438\u043d\u0446\u0438\u0434\u0435\u043d\u0442\u0430\u043c\u0438 \u0418\u0411": "\u0414\u0430\u043d\u043d\u044b\u0435 \u0443\u0442\u043e\u0447\u043d\u044f\u044e\u0442\u0441\u044f",
  "\u0421\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0435 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043d\u0430",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u0443\u0441\u0442\u0440\u0430\u043d\u0435\u043d\u0438\u044f": "\u041e\u0431\u043d\u043e\u0432\u043b\u0435\u043d\u0438\u0435 \u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u043d\u043e\u0433\u043e \u043e\u0431\u0435\u0441\u043f\u0435\u0447\u0435\u043d\u0438\u044f",
  "\u0421\u043f\u043e\u0441\u043e\u0431 \u044d\u043a\u0441\u043f\u043b\u0443\u0430\u0442\u0430\u0446\u0438\u0438": "\u0418\u0441\u0447\u0435\u0440\u043f\u0430\u043d\u0438\u0435 \u0440\u0435\u0441\u0443\u0440\u0441\u043e\u0432",
  "\u0421\u0441\u044b\u043b\u043a\u0438 \u043d\u0430 \u0438\u0441\u0442\u043e\u0447\u043d\u0438\u043a\u0438": "https://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa\nhttps://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383\nhttps://git.kernel.org/stable/c/ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29\nhttps://www.cve.org/CVERecord?id=CVE-2021-47546\nhttps://lore.kernel.org/linux-cve-announce/2024052440-CVE-2021-47546-f25b@gregkh/\nhttps://git.kernel.org/linus/cdef485217d30382f3bf6448c54b4401648fe3f1\nhttps://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commit/?h=v5.10.176-lvc1\u0026id=209d35ee34e25f9668c404350a1c86d914c54ffa\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.4.164\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.84\nhttps://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.7\nhttps://security-tracker.debian.org/tracker/CVE-2021-47546\nhttps://ubuntu.com/security/CVE-2021-47546",
  "\u0421\u0442\u0430\u0442\u0443\u0441 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u041f\u043e\u0434\u0442\u0432\u0435\u0440\u0436\u0434\u0435\u043d\u0430 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442\u0435\u043b\u0435\u043c",
  "\u0422\u0438\u043f \u041f\u041e": "\u041e\u043f\u0435\u0440\u0430\u0446\u0438\u043e\u043d\u043d\u0430\u044f \u0441\u0438\u0441\u0442\u0435\u043c\u0430",
  "\u0422\u0438\u043f \u043e\u0448\u0438\u0431\u043a\u0438 CWE": "CWE-401",
  "\u0423\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u0438": "\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 2.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 4,6)\n\u0421\u0440\u0435\u0434\u043d\u0438\u0439 \u0443\u0440\u043e\u0432\u0435\u043d\u044c \u043e\u043f\u0430\u0441\u043d\u043e\u0441\u0442\u0438 (\u0431\u0430\u0437\u043e\u0432\u0430\u044f \u043e\u0446\u0435\u043d\u043a\u0430 CVSS 3.0 \u0441\u043e\u0441\u0442\u0430\u0432\u043b\u044f\u0435\u0442 5,5)"
}

CVE-2021-47546 (GCVE-0-2021-47546)

Vulnerability from cvelistv5 – Published: 2024-05-24 15:09 – Updated: 2026-05-23 15:20

Title

ipv6: fix memory leak in fib6_rule_suppress

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: fix memory leak in fib6_rule_suppress The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache. After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule"). The problem with that change is that the generic `args->flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed. How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }' sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet. This patch exposes the protocol-specific flags to the protocol specific `suppress` function, and check the protocol-specific `flags` argument for RT6_LOOKUP_F_DST_NOREF instead of the generic FIB_LOOKUP_NOREF when decreasing the refcount, like this. [1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71 [2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-06-17 17:34 UTC

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/ee38eb8cf9a732388…
https://git.kernel.org/stable/c/209d35ee34e25f966…
https://git.kernel.org/stable/c/8ef8a76a340ebdb2c…
https://git.kernel.org/stable/c/cdef485217d30382f…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ca7a03c4175366a92cee0ccc4fec0038c3266e26 , < ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29 (git) Affected: ca7a03c4175366a92cee0ccc4fec0038c3266e26 , < 209d35ee34e25f9668c404350a1c86d914c54ffa (git) Affected: ca7a03c4175366a92cee0ccc4fec0038c3266e26 , < 8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 (git) Affected: ca7a03c4175366a92cee0ccc4fec0038c3266e26 , < cdef485217d30382f3bf6448c54b4401648fe3f1 (git) Affected: d37c966752043733eb847dd897d6e3405084c559 (git) Affected: ecc265624956ea784cb2bd2b31a95bd54c4f5f13 (git) Affected: 5.2.19 , < 5.3 (semver) Affected: 5.3.4 , < 5.4 (semver)
Linux	Linux	Affected: 5.4 Unaffected: 0 , < 5.4 (semver) Unaffected: 5.4.164 , ≤ 5.4.* (semver) Unaffected: 5.10.84 , ≤ 5.10.* (semver) Unaffected: 5.15.7 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix)

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        },
        {
          "url": "https://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa"
        },
        {
          "url": "https://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383"
        },
        {
          "url": "https://git.kernel.org/stable/c/cdef485217d30382f3bf6448c54b4401648fe3f1"
        }
      ],
      "title": "ipv6: fix memory leak in fib6_rule_suppress",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47546",
    "datePublished": "2024-05-24T15:09:51.286Z",
    "dateReserved": "2024-05-24T15:02:54.829Z",
    "dateUpdated": "2026-05-23T15:20:10.607Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

BDU:2025-04360 (CVE-2021-47546)

CVE-2021-47546 (GCVE-0-2021-47546)

Tags

Sightings

Nomenclature

Related by attack behaviour