CVE-2026-53346

In the Linux kernel, the following vulnerability has been resolved:

rust: arm64: set uwtable llvm module flag for CONFIG_UNWIND_TABLES

Due to a rustc bug [1] the -Cforce-unwind-tables=y flag only emits the uwtable annotation for functions, but not for the module. This means that compiler-generated functions such as asan.module_ctor do not receive the uwtable annotation.

When CONFIG_UNWIND_PATCH_PAC_INTO_SCS is enabled, this leads to boot failures because the dwarf information emitted for the kasan constructors is wrong, which causes the SCS boot patching code to patch the constructor in an illegal manner. Specifically, the paciasp instruction is patched, but the autiasp instruction is not. This mismatch leads to a crash when the constructor is called during boot.

==================================================================
BUG: KASAN: global-out-of-bounds in do_basic_setup+0x4c/0x90
Read of size 8 at addr ffffffe3cc7eb488 by task swapper/0/1

Specifically the faulting instruction is the (*fn)() to invoke the constructor in do_ctors() of the init/main.c file.

Once the fix lands in rustc, this flag can be made conditional on the rustc version. Note that passing the flag on a rustc with the fix present has no effect.

[ The fix [1] has landed for Rust 1.98.0 (expected release on 2026-08-20).

Thus add a version check as discussed.

- Miguel ]

[ Adjusted link and comment. - Miguel ]

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/7de13410f59e59b21d3c268a6e22d40f5d9d8a54
• https://git.kernel.org/stable/c/ac35b5580ace12e5d0a0b5e61e36d2c4e1ffa29c
• https://git.kernel.org/stable/c/bde772ee239720af216fb0b14753971059e132dc
• https://git.kernel.org/stable/c/d0f25a1755f2c15b1746379c8d9d7dfde85f58f5