Ubuntu Security Notices

Recent content on Ubuntu security notices

It was discovered that Dnsmasq incorrectly handled certain wildcard
synthesized NSEC records. A remote attacker could possibly use this issue
to prove the non-existence of hostnames that actually exist.
(CVE-2017-15107)

It was discovered that Dnsmasq incorrectly handled certain large DNS
packets. A remote attacker could possibly use this issue to cause Dnsmasq
to crash, resulting in a denial of service. (CVE-2019-14513)

USN-4916-1 fixed vulnerabilities in the Linux kernel. Unfortunately,
the fix for CVE-2021-3493 introduced a memory leak in some situations.
This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

It was discovered that the overlayfs implementation in the Linux kernel did
not properly validate the application of file system capabilities with
respect to user namespaces. A local attacker could use this to gain
elevated privileges. (CVE-2021-3493)

Piotr Krysiuk discovered that the BPF JIT compiler for x86 in the Linux
kernel did not properly validate computation of branch displacements in
some situations. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-29154)

Laszlo Ersek discovered that EDK II incorrectly handled recursion. A
remote attacker could possibly use this issue to cause EDK II to consume
resources, leading to a denial of service. (CVE-2021-28210)

Satoshi Tanda discovered that EDK II incorrectly handled decompressing
certain images. A remote attacker could use this issue to cause EDK II to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2021-28211)

USN-4922-1: Ruby vulnerability

20 April 2021, 5:01 pm

Juho Nurminen discovered that the REXML gem bundled with Ruby incorrectly
parsed and serialized XML documents. A remote attacker could possibly use
this issue to perform an XML round-trip attack.
It was discovered that libcaca incorrectly handled certain images.
An attacker could possibly use this issue to execute arbitrary code.
USN-4918-1 fixed several vulnerabilities in ClamAV. This update provides
the corresponding update for Ubuntu 14.04 ESM.
Original advisory details:

It was discovered that ClamAV incorrectly handled parsing Excel documents.
A remote attacker could possibly use this issue to cause ClamAV to hang,
resulting in a denial of service. (CVE-2021-1252)

It was discovered that ClamAV incorrectly handled parsing PDF documents. A
remote attacker could possibly use this issue to cause ClamAV to crash,
resulting in a denial of service. (CVE-2021-1404)

It was discovered that ClamAV incorrectly handled parsing email. A remote
attacker could possibly use this issue to cause ClamAV to crash, resulting
in a denial of service. (CVE-2021-1405)

USN-4563-2: NTP vulnerability

20 April 2021, 1:38 pm

USN-4563-1 fixed a vulnerability in NTP. This update provides the
corresponding update for Ubuntu 20.04 LTS and Ubuntu 20.10.

Original advisory details:

It was discovered that the fix for CVE-2018-7182 introduced a NULL pointer
dereference into NTP. An attacker could use this vulnerability to cause a
denial of service (crash).

It was discovered that OpenSLP did not properly validate URLs. A remote
attacker could use this issue to cause OpenSLP to crash or possibly execute
arbitrary code.
It was discovered that ClamAV incorrectly handled parsing Excel documents.
A remote attacker could possibly use this issue to cause ClamAV to hang,
resulting in a denial of service. (CVE-2021-1252)

It was discovered that ClamAV incorrectly handled parsing PDF documents. A
remote attacker could possibly use this issue to cause ClamAV to crash,
resulting in a denial of service. (CVE-2021-1404)

It was discovered that ClamAV incorrectly handled parsing email. A remote
attacker could possibly use this issue to cause ClamAV to crash, resulting
in a denial of service. (CVE-2021-1405)

It was discovered that the overlayfs implementation in the Linux kernel did
not properly validate the application of file system capabilities with
respect to user namespaces. A local attacker could use this to gain
elevated privileges. (CVE-2021-3493)

Vincent Dehors discovered that the shiftfs file system in the Ubuntu Linux
kernel did not properly handle faults in copy_from_user() when passing
through ioctls to an underlying file system. A local attacker could use
this to cause a denial of service (memory exhaustion) or execute arbitrary
code. (CVE-2021-3492)

Piotr Krysiuk discovered that the BPF JIT compiler for x86 in the Linux
kernel did not properly validate computation of branch displacements in
some situations. A local attacker could use this to cause a denial of
service (system crash) or possibly execute arbitrary code. (CVE-2021-29154)