Canonical: Security Vulnerabilities
The eBPF ALU32 bounds tracking for bitwise ops (AND, OR and XOR) in the Linux kernel did not properly update 32-bit bounds, which could be turned into out of bounds reads and writes in the Linux kernel and therefore, arbitrary code execution. This issue was fixed via commit 049c4e13714e ("bpf: Fix alu32 const subreg bound tracking on bitwise operations") (v5.13-rc4) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. The AND/OR issues were introduced by commit 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking") (5.7-rc1) and the XOR variant was introduced by 2921c90d4718 ("bpf:Fix a verifier failure with xor") ( 5.10-rc1).
CVSS Score
7.8
EPSS Score
0.04
Published
2021-06-04
The io_uring subsystem in the Linux kernel allowed the MAX_RW_COUNT limit to be bypassed in the PROVIDE_BUFFERS operation, which led to negative values being usedin mem_rw when reading /proc/<PID>/mem. This could be used to create a heap overflow leading to arbitrary code execution in the kernel. It was addressed via commit d1f82808877b ("io_uring: truncate lengths larger than MAX_RW_COUNT on provide buffers") (v5.13-rc1) and backported to the stable kernels in v5.12.4, v5.11.21, and v5.10.37. It was introduced in ddf0322db79c ("io_uring: add IORING_OP_PROVIDE_BUFFERS") (v5.7-rc1).
CVSS Score
7.8
EPSS Score
0.0
Published
2021-06-04
OpenVPN 2.5.1 and earlier versions allows a remote attackers to bypass authentication and access control channel data on servers configured with deferred authentication, which can be used to potentially trigger further information leaks.
CVSS Score
7.5
EPSS Score
0.002
Published
2021-04-26
CVE-2021-3493
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.
Known exploited
CVSS Score
8.8
EPSS Score
0.722
Published
2021-04-17
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.
CVSS Score
8.8
EPSS Score
0.234
Published
2021-04-17
The unity-firefox-extension package could be tricked into dropping a C callback which was still in use, which Firefox would then free, causing Firefox to crash. This could be achieved by adding an action to the launcher and updating it with new callbacks until the libunity-webapps rate limit was hit. Fixed in 3.0.0+14.04.20140416-0ubuntu1.14.04.1 of unity-firefox-extension and in all versions of libunity-webapps by shipping an empty unity-firefox-extension package, thus disabling the extension entirely and invalidating the attack against the libunity-webapps package.
CVSS Score
4.3
EPSS Score
0.002
Published
2021-04-07
The unity-firefox-extension package could be tricked into destroying the Unity webapps context, causing Firefox to crash. This could be achieved by spinning the event loop inside the webapps initialization callback. Fixed in 3.0.0+14.04.20140416-0ubuntu1.14.04.1 by shipping an empty package, thus disabling the extension entirely.
CVSS Score
4.3
EPSS Score
0.002
Published
2021-04-07
The bpf verifier in the Linux kernel did not properly handle mod32 destination register truncation when the source register was known to be 0. A local attacker with the ability to load bpf programs could use this gain out-of-bounds reads in kernel memory leading to information disclosure (kernel memory), and possibly out-of-bounds writes that could potentially lead to code execution. This issue was addressed in the upstream kernel in commit 9b00f1b78809 ("bpf: Fix truncation handling for mod32 dst reg wrt zero") and in Linux stable kernels 5.11.2, 5.10.19, and 5.4.101.
CVSS Score
7.8
EPSS Score
0.001
Published
2021-03-23
An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c has an off-by-one error (with a resultant integer underflow) affecting out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-10d2bb2e6b1d.
CVSS Score
6.0
EPSS Score
0.002
Published
2021-03-20
An issue was discovered in the Linux kernel before 5.11.8. kernel/bpf/verifier.c performs undesirable out-of-bounds speculation on pointer arithmetic, leading to side-channel attacks that defeat Spectre mitigations and obtain sensitive information from kernel memory, aka CID-f232326f6966. This affects pointer types that do not define a ptr_limit.
CVSS Score
4.7
EPSS Score
0.0
Published
2021-03-20