Quick answers
- Is CVE-2026-119131 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-119131 being exploited in the wild.
- How severe is CVE-2026-119131?
- Medium severity, with a CVSS score of 5.3, published 29 October 2026.
- Which products and versions are affected?
- Bytecode Alliance Wasmtime 46.0.0 before 48.0.6, 49.0.0 before 49.0.3.
- Is there a fix for CVE-2026-119131?
- Yes: fixed in Wasmtime 48.0.6, 49.0.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-119131 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-119131?
- Check whether you run Bytecode Alliance Wasmtime at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: Wasmtime 48.0.6, 49.0.3
Technical details
The vulnerability exists in wasmtime-wasi-http's dependency on the http crate, which stores the byte index of the '?' query parameter delimiter as a u16. When the '?' appears after byte 65535, the index wraps around, leading to an invalid character offset and causing a panic in the http crate when it attempts to split the URL string. A guest module can trigger this via the set-path-with-query WASI call with a URL of any length, resulting in a host panic without requiring any privileges or user interaction.
Affected products
- Bytecode Alliance Wasmtime 46.0.0 before 48.0.6, 49.0.0 before 49.0.3
Timeline
- 2026-10-14: disclosed: GitHub Security Advisory GHSA-w36r-2hch-9xp9 published
- 2026-10-29: advisory: CVE-2026-119131 published