Debian Security Advisory

DSA-4941-1 linux -- security update

Date Reported:
20 Jul 2021
Affected Packages:
Security database references:
In Mitre's CVE dictionary: CVE-2020-36311, CVE-2021-3609, CVE-2021-33909, CVE-2021-34693.
More information:

Several vulnerabilities have been discovered in the Linux kernel that may lead to a privilege escalation, denial of service or information leaks.

  • CVE-2020-36311

    A flaw was discovered in the KVM subsystem for AMD CPUs, allowing an attacker to cause a denial of service by triggering destruction of a large SEV VM.

  • CVE-2021-3609

    Norbert Slusarek reported a race condition vulnerability in the CAN BCM networking protocol, allowing a local attacker to escalate privileges.

  • CVE-2021-33909

    The Qualys Research Labs discovered a size_t-to-int conversion vulnerability in the Linux kernel's filesystem layer. An unprivileged local attacker able to create, mount, and then delete a deep directory structure whose total path length exceeds 1GB, can take advantage of this flaw for privilege escalation.

    Details can be found in the Qualys advisory at

  • CVE-2021-34693

    Norbert Slusarek discovered an information leak in the CAN BCM networking protocol. A local attacker can take advantage of this flaw to obtain sensitive information from kernel stack memory.

For the stable distribution (buster), these problems have been fixed in version 4.19.194-3.

We recommend that you upgrade your linux packages.

For the detailed security status of linux please refer to its security tracker page at: