Redhat » Enterprise Linux » 8.0 : Security Vulnerabilities, CVEs,

A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.

A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe and push_pipe functions in the Linux kernel and could thus contain stale values. An unprivileged local user could use this flaw to write to pages in the page cache backed by read only files and as such escalate their privileges on the system.

A vulnerability was found in the Linux kernel’s cgroup_release_agent_write in the kernel/cgroup/cgroup-v1.c function. This flaw, under certain circumstances, allows the use of the cgroups v1 release_agent feature to escalate privileges and bypass the namespace isolation unexpectedly.

A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.

In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to create a ptrace relationship, which allows local users to obtain root access by leveraging certain scenarios with a parent-child process relationship, where a parent drops privileges and calls execve (potentially allowing control by an attacker). One contributing factor is an object lifetime issue (which can also cause a panic). Another contributing factor is incorrect marking of a ptrace relationship as privileged, which is exploitable through (for example) Polkit's pkexec helper with PTRACE_TRACEME. NOTE: SELinux deny_ptrace might be a usable workaround in some environments.

In the Linux kernel before 4.20.14, expand_downwards in mm/mmap.c lacks a check for the mmap minimum address, which makes it easier for attackers to exploit kernel NULL pointer dereferences on non-SMAP platforms. This is related to a capability check for the wrong task.

runc through 1.0-rc6, as used in Docker before 18.09.2 and other products, allows attackers to overwrite the host runc binary (and consequently obtain host root access) by leveraging the ability to execute a command as root within one of these types of containers: (1) a new container with an attacker-controlled image, or (2) an existing container, to which the attacker previously had write access, that can be attached with docker exec. This occurs because of file-descriptor mishandling, related to /proc/self/exe.

A use-after-free vulnerability was found in the ProcRenderAddGlyphs() function of Xorg servers. This issue occurs when AllocateGlyph() is called to store new glyphs sent by the client to the X server, potentially resulting in multiple entries pointing to the same non-refcounted glyphs. Consequently, ProcRenderAddGlyphs() may free a glyph, leading to a use-after-free scenario when the same glyph pointer is subsequently accessed. This flaw allows an authenticated attacker to execute arbitrary code on the system by sending a specially crafted request.

A heap-based buffer over-read vulnerability was found in the X.org server's ProcAppleDRICreatePixmap() function. This issue occurs when byte-swapped length values are used in replies, potentially leading to memory leakage and segmentation faults, particularly when triggered by a client with a different endianness. This vulnerability could be exploited by an attacker to cause the X server to read heap memory values and then transmit them back to the client until encountering an unmapped page, resulting in a crash. Despite the attacker's inability to control the specific memory copied into the replies, the small length values typically stored in a 32-bit integer can result in significant attempted out-of-bounds reads.

A heap-based buffer over-read vulnerability was found in the X.org server's ProcXIPassiveGrabDevice() function. This issue occurs when byte-swapped length values are used in replies, potentially leading to memory leakage and segmentation faults, particularly when triggered by a client with a different endianness. This vulnerability could be exploited by an attacker to cause the X server to read heap memory values and then transmit them back to the client until encountering an unmapped page, resulting in a crash. Despite the attacker's inability to control the specific memory copied into the replies, the small length values typically stored in a 32-bit integer can result in significant attempted out-of-bounds reads.

A heap-based buffer over-read vulnerability was found in the X.org server's ProcXIGetSelectedEvents() function. This issue occurs when byte-swapped length values are used in replies, potentially leading to memory leakage and segmentation faults, particularly when triggered by a client with a different endianness. This vulnerability could be exploited by an attacker to cause the X server to read heap memory values and then transmit them back to the client until encountering an unmapped page, resulting in a crash. Despite the attacker's inability to control the specific memory copied into the replies, the small length values typically stored in a 32-bit integer can result in significant attempted out-of-bounds reads.

A flaw has been discovered in GnuTLS where an application crash can be induced when attempting to verify a specially crafted .pem bundle using the "certtool --verify-chain" command.

Relax-and-Recover (aka ReaR) through 2.7 creates a world-readable initrd when using GRUB_RESCUE=y. This allows local attackers to gain access to system secrets otherwise only readable by root.

A heap buffer overflow flaw was found in the DisableDevice function in the X.Org server. This issue may lead to an application crash or, in some circumstances, remote code execution in SSH X11 forwarding environments.

A flaw was found in X.Org server. In the XISendDeviceHierarchyEvent function, it is possible to exceed the allocated array length when certain new device IDs are added to the xXIHierarchyInfo struct. This can trigger a heap buffer overflow condition, which may lead to an application crash or remote code execution in SSH X11 forwarding environments.

A flaw was found in QEMU. An assertion failure was present in the update_sctp_checksum() function in hw/net/net_tx_pkt.c when trying to calculate the checksum of a short-sized fragmented packet. This flaw allows a malicious guest to crash QEMU and cause a denial of service condition.

A double free vulnerability was found in QEMU virtio devices (virtio-gpu, virtio-serial-bus, virtio-crypto), where the mem_reentrancy_guard flag insufficiently protects against DMA reentrancy issues. This issue could allow a malicious privileged guest to crash the QEMU process on the host, resulting in a denial of service or allow arbitrary code execution within the context of the QEMU process on the host.

A timing-based side-channel flaw exists in the rust-openssl package, which could be sufficient to recover a plaintext across a network in a Bleichenbacher-style attack. To achieve successful decryption, an attacker would have to be able to send a large number of trial messages for decryption. The vulnerability affects the legacy PKCS#1v1.5 RSA encryption padding mode.

A flaw was found in PCP. The default pmproxy configuration exposes the Redis server backend to the local network, allowing remote command execution with the privileges of the Redis user. This issue can only be exploited when pmproxy is running. By default, pmproxy is not running and needs to be started manually. The pmproxy service is usually started from the 'Metrics settings' page of the Cockpit web interface. This flaw affects PCP versions 4.3.4 and newer.

A flaw was found in Cockpit. Deleting a sosreport with a crafted name via the Cockpit web interface can lead to a command injection vulnerability, resulting in privilege escalation. This issue affects Cockpit versions 270 and newer.

A NULL pointer dereference flaw was found in the udevConnectListAllInterfaces() function in libvirt. This issue can occur when detaching a host interface while at the same time collecting the list of interfaces via virConnectListAllInterfaces API. This flaw could be used to perform a denial of service attack by causing the libvirt daemon to crash.

A flaw was found in the RPC library APIs of libvirt. The RPC server deserialization code allocates memory for arrays before the non-negative length check is performed by the C API entry points. Passing a negative length to the g_new0 function results in a crash due to the negative length being treated as a huge positive number. This flaw allows a local, unprivileged user to perform a denial of service attack by causing the libvirt daemon to crash.

A flaw was found in osbuild-composer. A condition can be triggered that disables GPG verification for package repositories, which can expose the build phase to a Man-in-the-Middle attack, allowing untrusted code to be installed into an image being built.

A timing-based side-channel flaw was found in libgcrypt's RSA implementation. This issue may allow a remote attacker to initiate a Bleichenbacher-style attack, which can lead to the decryption of RSA ciphertexts.

A double-free vulnerability was found in libdwarf. In a multiply-corrupted DWARF object, libdwarf may try to dealloc(free) an allocation twice, potentially causing unpredictable and various results.