Time-of-check Time-of-use (TOCTOU) Race Condition

Waitress is a Web Server Gateway Interface server for Python 2 and 3. A remote client may send a request that is exactly recv_bytes (defaults to 8192) long, followed by a secondary request using HTTP pipelining. When request lookahead is disabled (default) we won't read any more requests, and when the first request fails due to a parsing error, we simply close the connection. However when request lookahead is enabled, it is possible to process and receive the first request, start sending the error message back to the client while we read the next request and queue it. This will allow the secondary request to be serviced by the worker thread while the connection should be closed. Waitress 3.0.1 fixes the race condition. As a workaround, disable channel_request_lookahead, this is set to 0 by default disabling this feature.Show less

In the Linux kernel, the following vulnerability has been resolved: net: dsa: improve shutdown sequence Alexander Sverdlin presents 2 problems during shutdown with the lan9303 driver. One is specific to lan9303 and the other just happens to reproduce there. The first problem is that lan9303 is unique among DSA drivers in that it calls dev_get_drvdata() at "arbitrary runtime" (not probe, not shutdown, not remove): phy_state_machine() -> ... -> dsa_user_phy_read() -> ds->ops->phy_read() -> lan9303_phy_read() -> chip->ops->phy_read() -> lan9303_mdio_phy_read() -> dev_get_drvdata() But we never stop the phy_state_machine(), so it may continue to run after dsa_switch_shutdown(). Our common pattern in all DSA drivers is to set drvdata to NULL to suppress the remove() method that may come afterwards. But in this case it will result in an NPD. The second problem is that the way in which we set dp->conduit->dsa_ptr = NULL; is concurrent with receive packet processing. dsa_switch_rcv() checks once whether dev->dsa_ptr is NULL, but afterwards, rather than continuing to use that non-NULL value, dev->dsa_ptr is dereferenced again and again without NULL checks: dsa_conduit_find_user() and many other places. In between dereferences, there is no locking to ensure that what was valid once continues to be valid. Both problems have the common aspect that closing the conduit interface solves them. In the first case, dev_close(conduit) triggers the NETDEV_GOING_DOWN event in dsa_user_netdevice_event() which closes user ports as well. dsa_port_disable_rt() calls phylink_stop(), which synchronously stops the phylink state machine, and ds->ops->phy_read() will thus no longer call into the driver after this point. In the second case, dev_close(conduit) should do this, as per Documentation/networking/driver.rst: | Quiescence | ---------- | | After the ndo_stop routine has been called, the hardware must | not receive or transmit any data. All in flight packets must | be aborted. If necessary, poll or wait for completion of | any reset commands. So it should be sufficient to ensure that later, when we zeroize conduit->dsa_ptr, there will be no concurrent dsa_switch_rcv() call on this conduit. The addition of the netif_device_detach() function is to ensure that ioctls, rtnetlinks and ethtool requests on the user ports no longer propagate down to the driver - we're no longer prepared to handle them. The race condition actually did not exist when commit 0650bf52b31f ("net: dsa: be compatible with masters which unregister on shutdown") first introduced dsa_switch_shutdown(). It was created later, when we stopped unregistering the user interfaces from a bad spot, and we just replaced that sequence with a racy zeroization of conduit->dsa_ptr (one which doesn't ensure that the interfaces aren't up).Show less

A Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in the AgentD process of Juniper Networks Junos OS allows an attacker who is already causing impact to established sessions which generates counter changes picked up by the AgentD process during telemetry polling, to move the AgentD process into a state where AgentD attempts to reap an already destroyed sensor. This reaping attempt then leads to memory corruption causing the FPC to crash which is a Denial of Service (DoS). The FPC will recover automatically without user intervention after the crash. This issue affects Junos OS:  * All versions before 21.4R3-S9 * From 22.2 before 22.2R3-S5, * From 22.3 before 22.3R3-S4, * From 22.4 before 22.4R3-S3, * From 23.2 before 23.2R2-S2, * From 23.4 before 23.4R2. This issue does not affect Junos OS Evolved.Show less

Adobe Commerce versions 2.4.7-p2, 2.4.6-p7, 2.4.5-p9, 2.4.4-p10 and earlier are affected by a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability that could lead to a security feature bypass. An attacker could exploit this vulnerability to alter a condition between the check and the use of a resource, having a low impact on integrity. Exploitation of this issue requires user interaction.Show less

Wasmtime is an open source runtime for WebAssembly. Under certain concurrent event orderings, a `wasmtime::Engine`'s internal type registry was susceptible to double-unregistration bugs due to a race condition, leading to panics and potentially type registry corruption. That registry corruption could, following an additional and particular sequence of concurrent events, lead to violations of WebAssembly's control-flow integrity (CFI) and type safety. Users that do not use `wasmtime::Engine` across multiple threads are not affected. Users that only create new modules across threads over time are additionally not affected. Reproducing this bug requires creating and dropping multiple type instances (such as `wasmtime::FuncType` or `wasmtime::ArrayType`) concurrently on multiple threads, where all types are associated with the same `wasmtime::Engine`. **Wasm guests cannot trigger this bug.** See the "References" section below for a list of Wasmtime types-related APIs that are affected. Wasmtime maintains an internal registry of types within a `wasmtime::Engine` and an engine is shareable across threads. Types can be created and referenced through creation of a `wasmtime::Module`, creation of `wasmtime::FuncType`, or a number of other APIs where the host creates a function (see "References" below). Each of these cases interacts with an engine to deduplicate type information and manage type indices that are used to implement type checks in WebAssembly's `call_indirect` function, for example. This bug is a race condition in this management where the internal type registry could be corrupted to trigger an assert or contain invalid state. Wasmtime's internal representation of a type has individual types (e.g. one-per-host-function) maintain a registration count of how many time it's been used. Types additionally have state within an engine behind a read-write lock such as lookup/deduplication information. The race here is a time-of-check versus time-of-use (TOCTOU) bug where one thread atomically decrements a type entry's registration count, observes zero registrations, and then acquires a lock in order to unregister that entry. However, between when this first thread observed the zero-registration count and when it acquires that lock, another thread could perform the following sequence of events: re-register another copy of the type, which deduplicates to that same entry, resurrecting it and incrementing its registration count; then drop the type and decrement its registration count; observe that the registration count is now zero; acquire the type registry lock; and finally unregister the type. Now, when the original thread finally acquires the lock and unregisters the entry, it is the second time this entry has been unregistered. This bug was originally introduced in Wasmtime 19's development of the WebAssembly GC proposal. This bug affects users who are not using the GC proposal, however, and affects Wasmtime in its default configuration even when the GC proposal is disabled. Wasmtime users using 19.0.0 and after are all affected by this issue. We have released the following Wasmtime versions, all of which have a fix for this bug: * 21.0.2 * 22.0.1 * 23.0.3 * 24.0.1 * 25.0.2. If your application creates and drops Wasmtime types on multiple threads concurrently, there are no known workarounds. Users are encouraged to upgrade to a patched release.Show less

NVIDIA Container Toolkit 1.16.1 or earlier contains a vulnerability in the default mode of operation allowing a specially crafted container image to create empty files on the host file system. This does not impact use cases where CDI is used. A successful exploit of this vulnerability may lead to data tampering.Show less

NVIDIA Container Toolkit 1.16.1 or earlier contains a Time-of-check Time-of-Use (TOCTOU) vulnerability when used with default configuration where a specifically crafted container image may gain access to the host file system. This does not impact use cases where CDI is used. A successful exploit of this vulnerability may lead to code execution, denial of service, escalation of privileges, information disclosure, and data tampering.Show less

This vulnerability occurs when an attacker exploits a race condition between the time a file is checked and the time it is used (TOCTOU). By exploiting this race condition, an attacker can write arbitrary files to the system. This could allow the attacker to execute malicious code and potentially cause file losses.Show less

A unauthenticated Remote Code Execution (RCE) vulnerability is found in the SO Planning online planning tool. If the public view setting is enabled, a attacker can upload a PHP-file that will be available for execution for a few milliseconds before it is removed, leading to execution of code on the underlying system. The vulnerability has been remediated in version 1.52.02.Show less

In the Linux kernel, the following vulnerability has been resolved: exec: Fix ToCToU between perm check and set-uid/gid usage When opening a file for exec via do_filp_open(), permission checking is done against the file's metadata at that moment, and on success, a file pointer is passed back. Much later in the execve() code path, the file metadata (specifically mode, uid, and gid) is used to determine if/how to set the uid and gid. However, those values may have changed since the permissions check, meaning the execution may gain unintended privileges. For example, if a file could change permissions from executable and not set-id: ---------x 1 root root 16048 Aug 7 13:16 target to set-id and non-executable: ---S------ 1 root root 16048 Aug 7 13:16 target it is possible to gain root privileges when execution should have been disallowed. While this race condition is rare in real-world scenarios, it has been observed (and proven exploitable) when package managers are updating the setuid bits of installed programs. Such files start with being world-executable but then are adjusted to be group-exec with a set-uid bit. For example, "chmod o-x,u+s target" makes "target" executable only by uid "root" and gid "cdrom", while also becoming setuid-root: -rwxr-xr-x 1 root cdrom 16048 Aug 7 13:16 target becomes: -rwsr-xr-- 1 root cdrom 16048 Aug 7 13:16 target But racing the chmod means users without group "cdrom" membership can get the permission to execute "target" just before the chmod, and when the chmod finishes, the exec reaches brpm_fill_uid(), and performs the setuid to root, violating the expressed authorization of "only cdrom group members can setuid to root". Re-check that we still have execute permissions in case the metadata has changed. It would be better to keep a copy from the perm-check time, but until we can do that refactoring, the least-bad option is to do a full inode_permission() call (under inode lock). It is understood that this is safe against dead-locks, but hardly optimal.Show less

Acrobat Reader versions 20.005.30636, 24.002.20965, 24.002.20964, 24.001.30123 and earlier are affected by a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability that could lead to privilege escalation. Exploitation of this issue require local low-privilege access to the affected system and attack complexity is high.Show less

Acrobat Reader versions 20.005.30636, 24.002.21005, 24.001.30159, 20.005.30655, 24.002.20965, 24.002.20964, 24.001.30123, 24.003.20054 and earlier are affected by a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability that could lead to arbitrary code execution. This vulnerability arises when the timing of actions changes the state of a resource between the checking of a condition and the use of the resource, allowing an attacker to manipulate the resource in a harmful way. Exploitation of this issue requires user interaction in that a victim must open a malicious file.Show less

Time-of-check Time-of-use (TOCTOU) race condition in pg_dump in PostgreSQL allows an object creator to execute arbitrary SQL functions as the user running pg_dump, which is often a superuser. The attack involves replacing another relation type with a view or foreign table. The attack requires waiting for pg_dump to start, but winning the race condition is trivial if the attacker retains an open transaction. Versions before PostgreSQL 16.4, 15.8, 14.13, 13.16, and 12.20 are affected.Show less