CVE-2026-24116
What it is
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.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 4.1 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Weakness
- CWE-125 · Out-of-bounds read
- Record status
- Analyzed
Affected
- Bytecodealliance Wasmtime < 36.0.5
- Bytecodealliance Wasmtime < 40.0.3
- Bytecodealliance Wasmtime < 41.0.1
Attack profile CVSS 4.0 · 4.1
- Attack vector
- Local
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- Low
- User interaction
- Active
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:4.0/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
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-24116.md and follow it. Check whether this project is affected by CVE-2026-24116. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://github.com/bytecodealliance/wasmtime/commit/728fa07184f8da2a046f48ef9b61f869dce133a6
- https://github.com/bytecodealliance/wasmtime/commit/799585fc362fcb991de147dd1a9f2ba0861ed440
- https://github.com/bytecodealliance/wasmtime/commit/ac92d9bb729ad3a6d93f0724c4c33a0c4a9c0227
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-vc8c-j3xm-xj73
References
- https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.memory_guard_size
- https://docs.rs/wasmtime/latest/wasmtime/struct.Config.html#method.signals_based_traps
- https://docs.wasmtime.dev/stability-release.html
- https://github.com/bytecodealliance/wasmtime/commit/728fa07184f8da2a046f48ef9b61f869dce133a6
- https://github.com/bytecodealliance/wasmtime/commit/799585fc362fcb991de147dd1a9f2ba0861ed440
- https://github.com/bytecodealliance/wasmtime/commit/ac92d9bb729ad3a6d93f0724c4c33a0c4a9c0227
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-vc8c-j3xm-xj73
- https://rustsec.org/advisories/RUSTSEC-2026-0006.html