Quick answers
- Is CVE-2026-115387 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-115387 being exploited in the wild.
- How severe is CVE-2026-115387?
- Medium severity, with a CVSS score of 6.2, published 22 October 2026.
- Which products and versions are affected?
- Bytecode Alliance Wasmtime before 36.0.16, 37.0.0 before 48.0.3, 49.0.0 before 49.0.1.
- Is there a fix for CVE-2026-115387?
- Yes: fixed in 36.0.16, 48.0.3, 49.0.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-115387 attacked?
- It is attacked with local access, in a software library.
- Am I affected by CVE-2026-115387?
- 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: 36.0.16, 48.0.3, 49.0.1
Technical details
The wasmtime-wasi crate fails to validate filesystem timestamp arguments (atim, mtim) before passing them to Rust's std::time::Duration::new, which panics on integer overflow when the microseconds field overflows into the seconds field. An attacker-controlled guest WASM program can trigger this panic by invoking path_filestat_set_times, fd_filestat_set_times, set-times, or set-times-at with overflow values like Timestamp { seconds: u64::MAX, microseconds: 1_000_000_000 }.
Affected products
- Bytecode Alliance Wasmtime before 36.0.16, 37.0.0 before 48.0.3, 49.0.0 before 49.0.1
Timeline
- 2026-09-24: disclosed
- 2026-10-22: advisory