UBUNTU-CVE-2021-20254

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    UBUNTU-CVE-2021-20254

    Published: 29 Apr 2021Last Modified: 22 Apr 2026
    Upstream:
    CVE-2021-20254

    Summary:

    Details: A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.

    References: https://ubuntu.com/security/CVE-2021-20254, https://www.samba.org/samba/security/CVE-2021-20254.html, https://ubuntu.com/security/notices/USN-4930-1, https://ubuntu.com/security/notices/USN-4931-1, https://www.cve.org/CVERecord?id=CVE-2021-20254

    Affected packages

    Package

    Name: samba

    Purl: pkg:deb/ubuntu/samba@2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11?arch=source&distro=trusty/esm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11

    Affected versions

    2:3.6.18-1ubuntu3

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
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