Rust wasmtime: Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext
Affects rust-wasmtimeSource GCVE Database
Not known to be exploited · CVSS 2.1 Low.
Data as of 5 Nov 2026, 12:35 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 2.1 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 2.6 |
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10rust-wasmtimepkg:deb/ubuntu/rust-wasmtime?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSrust-wasmtimepkg:deb/ubuntu/rust-wasmtime?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSrust-wasmtimepkg:deb/ubuntu/rust-wasmtime?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.
References
- ubuntu.com/security/CVE-2026-119133 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-119133 (opens in a new tab)
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-p79w-pv2r-29qp (opens in a new tab)
- vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.6-and-49.0.0-before-49.0.3-misaligned-vmcontext-via-exception-tags (opens in a new tab)