CVE-2026-24116
Wasmtime segfault or unused out-of-sandbox load with f64.copysign operator on x86-64
Description
Wasmtime is a runtime for WebAssembly. Starting in version 29.0.0 and prior to version 36.0.5, 40.0.3, and 41.0.1, on x86-64 platforms with AVX, Wasmtime's compilation of the `f64.copysign` WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but unless there is another bug in Cranelift this data is not visible to WebAssembly guests. Wasmtime 36.0.5, 40.0.3, and 41.0.1 have been released to fix this issue. Users are recommended to upgrade to the patched versions of Wasmtime. Other affected versions are not patched and users should updated to supported major version instead. This bug can be worked around by enabling signals-based-traps. While disabling guard pages can be a quick fix in some situations, it's not recommended to disabled guard pages as it is a key defense-in-depth measure of Wasmtime.
INFO
Published Date :
Jan. 27, 2026, 7:16 p.m.
Last Modified :
Feb. 12, 2026, 9:36 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Upgrade Wasmtime to a fixed version.
- Enable signals-based traps if upgrading is not possible.
- Avoid disabling guard pages if possible.
Public PoC/Exploit Available at Github
CVE-2026-24116 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-24116.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-24116 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-24116
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
A multi-fuzzer management utility for all of your Rust fuzzing needs 🧑🎤
afl fuzzing honggfuzz rust
Rust
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-24116 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-24116 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Feb. 12, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 29.0.0 up to (excluding) 36.0.5 *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 40.0.0 up to (excluding) 40.0.3 *cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:* versions from (including) 41.0.0 up to (excluding) 41.0.1 Added Reference Type GitHub, Inc.: https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.memory_guard_size Types: Product Added Reference Type GitHub, Inc.: https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.signals_based_traps Types: Product Added Reference Type GitHub, Inc.: https://docs.wasmtime.dev/stability-release.html Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/commit/728fa07184f8da2a046f48ef9b61f869dce133a6 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/commit/799585fc362fcb991de147dd1a9f2ba0861ed440 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/commit/ac92d9bb729ad3a6d93f0724c4c33a0c4a9c0227 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-vc8c-j3xm-xj73 Types: Patch, Vendor Advisory Added Reference Type GitHub, Inc.: https://rustsec.org/advisories/RUSTSEC-2026-0006.html Types: Third Party Advisory -
New CVE Received by [email protected]
Jan. 27, 2026
Action Type Old Value New Value Added Description Wasmtime is a runtime for WebAssembly. Starting in version 29.0.0 and prior to version 36.0.5, 40.0.3, and 41.0.1, on x86-64 platforms with AVX, Wasmtime's compilation of the `f64.copysign` WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but unless there is another bug in Cranelift this data is not visible to WebAssembly guests. Wasmtime 36.0.5, 40.0.3, and 41.0.1 have been released to fix this issue. Users are recommended to upgrade to the patched versions of Wasmtime. Other affected versions are not patched and users should updated to supported major version instead. This bug can be worked around by enabling signals-based-traps. While disabling guard pages can be a quick fix in some situations, it's not recommended to disabled guard pages as it is a key defense-in-depth measure of Wasmtime. Added CVSS V4.0 AV:L/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-125 Added Reference https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.memory_guard_size Added Reference https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.signals_based_traps Added Reference https://docs.wasmtime.dev/stability-release.html Added Reference https://github.com/bytecodealliance/wasmtime/commit/728fa07184f8da2a046f48ef9b61f869dce133a6 Added Reference https://github.com/bytecodealliance/wasmtime/commit/799585fc362fcb991de147dd1a9f2ba0861ed440 Added Reference https://github.com/bytecodealliance/wasmtime/commit/ac92d9bb729ad3a6d93f0724c4c33a0c4a9c0227 Added Reference https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-vc8c-j3xm-xj73 Added Reference https://rustsec.org/advisories/RUSTSEC-2026-0006.html