CVE-2026-121520

    Dashboard / Vulnerabilities / CVE-2026-121520

    CVE-2026-121520

    Published: 3 Nov 2026Last Modified: 8 Nov 2026

    Summary: Malicious client could set xattr value outside of BuildKit state directory

    Details: In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory. Extended attributes in the trusted. or security. namespaces may also be set, potentially giving a program on the host elevated privileges. This issue affects build services that accept build requests from untrusted users. The issue is fixed in v0.34.1.

    References: https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/121xxx/CVE-2026-121520.json, https://github.com/moby/buildkit/security/advisories/GHSA-w26x-xg27-7qjc, https://nvd.nist.gov/vuln/detail/CVE-2026-121520, https://github.com/moby/buildkit

    Affected packages

    Package

    Name:

    Purl:

    Affected ranges

    Type: GIT

    Events:

    Introduced- 0
    Fixed -f5b59a1f2fb25a0cb7072c398cab9aed7835da4e

    Affected versions

    v0.34.0-rc2
    v0.34.0-rc1

    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
    CVE-2026-121520 | CVE-DB