CVE-2021-41617

Publication date 26 September 2021

Last updated 11 February 2025

Ubuntu priority

Cvss 3 Severity Score

sshd in OpenSSH 6.2 through 8.x before 8.8, when certain non-default configurations are used, allows privilege escalation because supplemental groups are not initialized as expected. Helper programs for AuthorizedKeysCommand and AuthorizedPrincipalsCommand may run with privileges associated with group memberships of the sshd process, if the configuration specifies running the command as a different user.

Read the notes from the security team

Why is this CVE low priority?

Cannot be reproduced on Ubuntu since sshd drops groups early

Learn more about Ubuntu priority

Status

Show unmaintained releases

Package	Ubuntu Release	Status
openssh	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy FIPS Updates	Not affected
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.04 LTS focal	Fixed 1:8.2p1-4ubuntu0.11
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Fixed 1:7.2p2-4ubuntu2.10+esm2 Ubuntu Pro
	14.04 LTS trusty	Ignored end of ESM support, was needed
openssh-ssh1	24.10 oracular	Ignored
	24.04 LTS noble	Ignored
	23.10 mantic	Ignored end of life, was needed
	23.04 lunar	Ignored end of life, was needed
	22.10 kinetic	Ignored end of life, was needed
	22.04 LTS jammy	Ignored
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.04 LTS focal	Ignored
	18.04 LTS bionic	Ignored
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

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Notes

mdeslaur

openssh-ssh1 is only provided for compatibility with old devices that cannot be upgraded to modern protocols. We will not be providing any security support for the openssh-ssh1 package as it is insecure and should be used in trusted environments only. Only applies to non-default configurations where AuthorizedKeysCommand or AuthorizedPrincipalsCommand are used.

sespiros

Cannot reproduce since sshd for all releases drops supplementary groups early when it starts with setgroups(0, NULL).

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
openssh	Upstream: f3cbe43 Upstream: bf944e3

Severity score breakdown

Parameter	Value
Base score	7.0 · High
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	High
Vector	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H