Canonical Ubuntu Linux 18.04 Lts

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the xorg-hwe-18.04 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the xorg package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-17 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-16 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-15 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-14 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-13 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-8 package apport hooks, it could expose private data to other local users.

It was discovered that read_file() in apport/hookutils.py would follow symbolic links or open FIFOs. When this function is used by the openjdk-lts package apport hooks, it could expose private data to other local users.

The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

Overlayfs did not properly perform permission checking when copying up files in an overlayfs and could be exploited from within a user namespace, if, for example, unprivileged user namespaces were allowed. It was possible to have a file not readable by an unprivileged user to be copied to a mountpoint controlled by the user, like a removable device. This was introduced in kernel version 4.19 by commit d1d04ef ("ovl: stack file ops"). This was fixed in kernel version 5.8 by commits 56230d9 ("ovl: verify permissions in ovl_path_open()"), 48bd024 ("ovl: switch to mounter creds in readdir") and 05acefb ("ovl: check permission to open real file"). Additionally, commits 130fdbc ("ovl: pass correct flags for opening real directory") and 292f902 ("ovl: call secutiry hook in ovl_real_ioctl()") in kernel 5.8 might also be desired or necessary. These additional commits introduced a regression in overlay mounts within user namespaces which prevented access to files with ownership outside of the user namespace. This regression was mitigated by subsequent commit b6650da ("ovl: do not fail because of O_NOATIMEi") in kernel 5.11.

Use-after-free vulnerability in the Linux kernel exploitable by a local attacker due to reuse of a DCCP socket with an attached dccps_hc_tx_ccid object as a listener after being released. Fixed in Ubuntu Linux kernel 5.4.0-51.56, 5.3.0-68.63, 4.15.0-121.123, 4.4.0-193.224, 3.13.0.182.191 and 3.2.0-149.196.

Aptdaemon performed policykit checks after interacting with potentially untrusted files with elevated privileges. This affected versions prior to 1.1.1+bzr982-0ubuntu34.1, 1.1.1+bzr982-0ubuntu32.3, 1.1.1+bzr982-0ubuntu19.5, 1.1.1+bzr982-0ubuntu14.5.

The aptdaemon DBus interface disclosed file existence disclosure by setting Terminal/DebconfSocket properties, aka GHSL-2020-192 and GHSL-2020-196. This affected versions prior to 1.1.1+bzr982-0ubuntu34.1, 1.1.1+bzr982-0ubuntu32.3, 1.1.1+bzr982-0ubuntu19.5, 1.1.1+bzr982-0ubuntu14.5.

An Ubuntu-specific patch in PulseAudio created a race condition where the snap policy module would fail to identify a client connection from a snap as coming from a snap if SCM_CREDENTIALS were missing, allowing the snap to connect to PulseAudio without proper confinement. This could be exploited by an attacker to expose sensitive information. Fixed in 1:13.99.3-1ubuntu2, 1:13.99.2-1ubuntu2.1, 1:13.99.1-1ubuntu3.8, 1:11.1-1ubuntu7.11, and 1:8.0-0ubuntu3.15.

PackageKit's apt backend mistakenly treated all local debs as trusted. The apt security model is based on repository trust and not on the contents of individual files. On sites with configured PolicyKit rules this may allow users to install malicious packages.

In containerd (an industry-standard container runtime) before version 1.2.14 there is a credential leaking vulnerability. If a container image manifest in the OCI Image format or Docker Image V2 Schema 2 format includes a URL for the location of a specific image layer (otherwise known as a “foreign layer†), the default containerd resolver will follow that URL to attempt to download it. In v1.2.x but not 1.3.0 or later, the default containerd resolver will provide its authentication credentials if the server where the URL is located presents an HTTP 401 status code along with registry-specific HTTP headers. If an attacker publishes a public image with a manifest that directs one of the layers to be fetched from a web server they control and they trick a user or system into pulling the image, they can obtain the credentials used for pulling that image. In some cases, this may be the user's username and password for the registry. In other cases, this may be the credentials attached to the cloud virtual instance which can grant access to other cloud resources in the account. The default containerd resolver is used by the cri-containerd plugin (which can be used by Kubernetes), the ctr development tool, and other client programs that have explicitly linked against it. This vulnerability has been fixed in containerd 1.2.14. containerd 1.3 and later are not affected. If you are using containerd 1.3 or later, you are not affected. If you are using cri-containerd in the 1.2 series or prior, you should ensure you only pull images from trusted sources. Other container runtimes built on top of containerd but not using the default resolver (such as Docker) are not affected.

A flaw was found in the Linux kernel in versions before 5.9-rc7. Traffic between two Geneve endpoints may be unencrypted when IPsec is configured to encrypt traffic for the specific UDP port used by the GENEVE tunnel allowing anyone between the two endpoints to read the traffic unencrypted. The main threat from this vulnerability is to data confidentiality.

Multiple buffer overflow vulnerabilities were found in the QUIC image decoding process of the SPICE remote display system, before spice-0.14.2-1. Both the SPICE client (spice-gtk) and server are affected by these flaws. These flaws allow a malicious client or server to send specially crafted messages that, when processed by the QUIC image compression algorithm, result in a process crash or potential code execution.

In PHP versions 7.2.x below 7.2.34, 7.3.x below 7.3.23 and 7.4.x below 7.4.11, when PHP is processing incoming HTTP cookie values, the cookie names are url-decoded. This may lead to cookies with prefixes like __Host confused with cookies that decode to such prefix, thus leading to an attacker being able to forge cookie which is supposed to be secure. See also CVE-2020-8184 for more information.

In PHP versions 7.2.x below 7.2.34, 7.3.x below 7.3.23 and 7.4.x below 7.4.11, when AES-CCM mode is used with openssl_encrypt() function with 12 bytes IV, only first 7 bytes of the IV is actually used. This can lead to both decreased security and incorrect encryption data.

An untrusted pointer dereference flaw was found in Perl-DBI < 1.643. A local attacker who is able to manipulate calls to dbd_db_login6_sv() could cause memory corruption, affecting the service's availability.

A flaw was found in X.Org Server before xorg-x11-server 1.20.9. An Out-Of-Bounds access in XkbSetNames function may lead to a privilege escalation vulnerability. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

The Raccoon attack exploits a flaw in the TLS specification which can lead to an attacker being able to compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite. In such a case this would result in the attacker being able to eavesdrop on all encrypted communications sent over that TLS connection. The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections. Note that this issue only impacts DH ciphersuites and not ECDH ciphersuites. This issue affects OpenSSL 1.0.2 which is out of support and no longer receiving public updates. OpenSSL 1.1.1 is not vulnerable to this issue. Fixed in OpenSSL 1.0.2w (Affected 1.0.2-1.0.2v).