xen: missing memory barriers when accessing/allocating an event channel (XSA-340)

An issue was discovered in Xen through 4.14.x. There are missing memory barriers when accessing/allocating an event channel. Event channels control structures can be accessed lockless as long as the port is considered to be valid. Such a sequence is missing an appropriate memory barrier (e.g., smp_*mb()) to prevent both the compiler and CPU from re-ordering access. A malicious guest may be able to cause a hypervisor crash resulting in a Denial of Service (DoS). Information leak and privilege escalation cannot be excluded. Systems running all versions of Xen are affected. Whether a system is vulnerable will depend on the CPU and compiler used to build Xen. For all systems, the presence and the scope of the vulnerability depend on the precise re-ordering performed by the compiler used to build Xen. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code generation options). GCC documentation clearly suggests that re-ordering is possible. Arm systems will also be vulnerable if the CPU is able to re-order memory access. Please consult your CPU vendor. x86 systems are only vulnerable if a compiler performs re-ordering.

xen: missing unlock in XENMEM_acquire_resource error path (XSA-334)

An issue was discovered in Xen 4.14.x. There is a missing unlock in the XENMEM_acquire_resource error path. The RCU (Read, Copy, Update) mechanism is a synchronisation primitive. A buggy error path in the XENMEM_acquire_resource exits without releasing an RCU reference, which is conceptually similar to forgetting to unlock a spinlock. A buggy or malicious HVM stubdomain can cause an RCU reference to be leaked. This causes subsequent administration operations, (e.g., CPU offline) to livelock, resulting in a host Denial of Service. The buggy codepath has been present since Xen 4.12. Xen 4.14 and later are vulnerable to the DoS. The side effects are believed to be benign on Xen 4.12 and 4.13, but patches are provided nevertheless. The vulnerability can generally only be exploited by x86 HVM VMs, as these are generally the only type of VM that have a Qemu stubdomain. x86 PV and PVH domains, as well as ARM VMs, typically don't use a stubdomain. Only VMs using HVM stubdomains can exploit the vulnerability. VMs using PV stubdomains, or with emulators running in dom0, cannot exploit the vulnerability.

kernel: incorrect vsyscall page reference counting in get_gate_page function in mm/gup.c

get_gate_page in mm/gup.c in the Linux kernel 5.7.x and 5.8.x before 5.8.7 allows privilege escalation because of incorrect reference counting (caused by gate page mishandling) of the struct page that backs the vsyscall page. The result is a refcount underflow. This can be triggered by any 64-bit process that can use ptrace() or process_vm_readv(), aka CID-9fa2dd946743.

libproxy: uncontrolled recursion via an infinite stream response leading to stack exhaustion

url::recvline in url.cpp in libproxy 0.4.x through 0.4.15 allows a remote HTTP server to trigger uncontrolled recursion via a response composed of an infinite stream that lacks a newline character. This leads to stack exhaustion.

poppler: uncontrolled recursion in pdfinfo and pdftops

Uncontrolled Recursion in pdfinfo, and pdftops in poppler 0.89.0 allows remote attackers to cause a denial of service via crafted input.

Mikrotik RouterOs 6.44.5 (long-term tree) suffers from an stack exhaustion vulnerability in the /nova/bin/net process. An authenticated remote attacker can cause a Denial of Service due to overloading the systems CPU.

A logic vulnerability when handling the SaveGeneratorLong instruction in Facebook Hermes prior to commit b2021df620824627f5a8c96615edbd1eb7fdddfc allows attackers to potentially read out of bounds or theoretically execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.

The fb_unserialize function did not impose a depth limit for nested deserialization. That meant a maliciously constructed string could cause deserialization to recurse, leading to stack exhaustion. This issue affected HHVM prior to v4.32.3, between versions 4.33.0 and 4.56.0, 4.57.0, 4.58.0, 4.58.1, 4.59.0, 4.60.0, 4.61.0, 4.62.0.

exiv2: stack exhaustion issue in the printIFDStructure function may lead to DoS

A stack exhaustion issue in the printIFDStructure function of Exiv2 0.27 allows remote attackers to cause a denial of service (DOS) via a crafted file.

Stack overflow vulnerability in parse_array Cesanta MJS 1.20.1, allows remote attackers to cause a Denial of Service (DoS) via a crafted file.

Turcom TRCwifiZone through 2020-08-10 allows authentication bypass by visiting manage/control.php and ignoring 302 Redirect responses.

In imap_scan_tree_recursive in Claws Mail through 3.17.6, a malicious IMAP server can trigger stack consumption because of unlimited recursion into subdirectories during a rebuild of the folder tree.

Improper session expiration in Parse Server

Parse Server (npm package parse-server) broadcasts events to all clients without checking if the session token is valid. This allows clients with expired sessions to still receive subscription objects. It is not possible to create subscription objects with invalid session tokens. The issue is not patched.

Nested directory structure can lead to Uncontrolled Resource Consumption in freewvs

In freewvs before 0.1.1, a directory structure of more than 1000 nested directories can interrupt a freewvs scan due to Python's recursion limit and os.walk(). This can be problematic in a case where an administrator scans the dirs of potentially untrusted users. This has been patched in 0.1.1.

squirrelmail: use of unserialize function for the attachments value in compose.php

compose.php in SquirrelMail 1.4.22 calls unserialize for the $attachments value, which originates from an HTTP POST request. NOTE: the vendor disputes this because these two conditions for PHP object injection are not satisfied: existence of a PHP magic method (such as __wakeup or __destruct), and any attack-relevant classes must be declared before unserialize is called (or must be autoloaded).

squirrelmail: use of unserialize function for the mailtodata value in compose.php

compose.php in SquirrelMail 1.4.22 calls unserialize for the $mailtodata value, which originates from an HTTP GET request. This is related to mailto.php.

squid: DoS in TLS handshake

An issue was discovered in Squid before 4.12 and 5.x before 5.0.3. Due to use of a potentially dangerous function, Squid and the default certificate validation helper are vulnerable to a Denial of Service when opening a TLS connection to an attacker-controlled server for HTTPS. This occurs because unrecognized error values are mapped to NULL, but later code expects that each error value is mapped to a valid error string.

QEMU: ati-vga: infinite recursion in ati_mm_read/write calls may lead to DoS

ati-vga in hw/display/ati.c in QEMU 4.2.0 allows guest OS users to trigger infinite recursion via a crafted mm_index value during an ati_mm_read or ati_mm_write call.

A denial-of-service vulnerability exists in the Ethernet/IP server functionality of the EIP Stack Group OpENer 2.3 and development commit 8c73bf3. A large number of network requests in a small span of time can cause the running program to stop. An attacker can send a sequence of requests to trigger this vulnerability.

wireshark: NFS dissector crash (wnpa-sec-2020-08)

In Wireshark 3.2.0 to 3.2.3, 3.0.0 to 3.0.10, and 2.6.0 to 2.6.16, the NFS dissector could crash. This was addressed in epan/dissectors/packet-nfs.c by preventing excessive recursion, such as for a cycle in the directory graph on a filesystem.