Debian Security Advisory
DLA-2713-2 linux -- LTS security update
- Date Reported:
- 20 Jul 2021
- Affected Packages:
- Security database references:
- In the Debian bugtracking system: Bug 990072.
In Mitre's CVE dictionary: CVE-2021-3609, CVE-2021-21781, 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.
Norbert Slusarek reported a race condition vulnerability in the CAN BCM networking protocol, allowing a local attacker to escalate privileges.
"Lilith>_>" of Cisco Talos discovered that the Arm initialisation code does not fully initialise the
sigpagethat is mapped into user-space processes to support signal handling. This could result in leaking sensitive information, particularly when the system is rebooted.
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 https://www.qualys.com/2021/07/20/cve-2021-33909/sequoia-local-privilege-escalation-linux.txt
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 Debian 9 stretch, these problems have been fixed in version 4.9.272-2. This additionally fixes a regression in the previous update (#990072) that affected LXC.
We recommend that you upgrade your linux packages.
For the detailed security status of linux please refer to its security tracker page at: https://security-tracker.debian.org/tracker/linux
Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS