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CVE-2021-26933

CVE-2021-26933

This page contains facts from public vulnerability sources. Check the original advisory before updating.

An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory.

CVSS 5.5 · Medium · EPSS 0.3% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • n/a

    Versions
    • n/a: Affected

    No fix published

  • xen Debian:12

    Affected ranges
    • ECOSYSTEM: < 4.14.1+11-gb0b734a8b3-1

    Update to 4.14.1+11-gb0b734a8b3-1

  • xen Debian:13

    Affected ranges
    • ECOSYSTEM: < 4.14.1+11-gb0b734a8b3-1

    Update to 4.14.1+11-gb0b734a8b3-1

  • xen Debian:14

    Affected ranges
    • ECOSYSTEM: < 4.14.1+11-gb0b734a8b3-1

    Update to 4.14.1+11-gb0b734a8b3-1

  • xen Ubuntu:16.04:LTS

    Versions
    • 4.5.1-0ubuntu1
    • 4.5.1-0ubuntu2
    • 4.6.0-1ubuntu1
    • 4.6.0-1ubuntu2
    • 4.6.0-1ubuntu4
    • 4.6.0-1ubuntu4.1
    • 4.6.0-1ubuntu4.2
    • 4.6.0-1ubuntu4.3
    • 4.6.5-0ubuntu1
    • 4.6.5-0ubuntu1.1
    • 4.6.5-0ubuntu1.2
    • 4.6.5-0ubuntu1.4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:18.04:LTS

    Versions
    • 4.9.0-0ubuntu3
    • 4.9.0-0ubuntu4
    • 4.9.2-0ubuntu1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:20.04:LTS

    Versions
    • 4.9.2-0ubuntu2
    • 4.9.2-0ubuntu6
    • 4.9.2-0ubuntu7
    • 4.11.3+24-g14b62ab3e5-1ubuntu1
    • 4.11.3+24-g14b62ab3e5-1ubuntu2
    • 4.11.3+24-g14b62ab3e5-1ubuntu2.2
    • 4.11.3+24-g14b62ab3e5-1ubuntu2.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:22.04:LTS

    Versions
    • 4.11.4+24-gddaaccbbab-1ubuntu2
    • 4.16.0-1~ubuntu2
    • 4.16.0-1~ubuntu2.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:24.04:LTS

    Versions
    • 4.17.2-1
    • 4.17.2+55-g0b56bed864-1
    • 4.17.2+76-ge1f9cb16e2-1
    • 4.17.2+76-ge1f9cb16e2-1ubuntu1
    • 4.17.3+10-g091466ba55-1
    • 4.17.3+10-g091466ba55-1.1ubuntu2
    • 4.17.3+10-g091466ba55-1.1ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:25.10

    Versions
    • 4.20.0-1ubuntu1
    • 4.20.0+68-g35cb38b222-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:26.10

    Versions
    • 4.20.2+7-g1badcf5035-2build2
    • 4.20.2+37-g61ff35323e-1ubuntu1
    • 4.20.3+127-gc42374a105-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xen Ubuntu:26.04:LTS

    Versions
    • 4.20.0+68-g35cb38b222-1
    • 4.20.2+7-g1badcf5035-2
    • 4.20.2+7-g1badcf5035-2build2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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