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VulnerabilityPublished Updated

CVE-2025-62711: bytecodealliance wasmtime · Improper Handling of Exceptional Conditions

Affects bytecodealliance wasmtimeSource CVE Database V5

0

Not known to be exploited · CVSS 2.1 Low : upgrade to 38.0.3 when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 4.0 base score
2.1Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 38.0.3
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 24 Oct 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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 26 Oct 2026.

What to do

Upgrade github/bytecodealliance/wasmtime to 38.0.3.

Affected software

ProductAffectedFixed in
crates.iogithub/bytecodealliance/wasmtimepkg:cargo/github/bytecodealliance/wasmtimeOther threatsAffected
  • <38.0.3 >=38.0.0
Fixed in
  • 38.0.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The definitive mitigation for CVE-2025-62711 is to upgrade all affected Wasmtime instances to version 38.0.3 or later, where the vulnerability has been fixed. Organizations should implement a thorough inventory of systems and development environments using Wasmtime to ensure no outdated versions remain in production or testing. Additionally, auditing WebAssembly components for unexpected or malformed inputs can help detect attempts to exploit this vulnerability. Incorporating runtime monitoring and alerting for abnormal crashes or assertion failures in Wasmtime hosts can provide early warning of exploitation attempts. For environments where immediate patching is not feasible, isolating Wasmtime processes and limiting their privileges can reduce potential impact. Finally, integrating Wasmtime updates into continuous integration/continuous deployment (CI/CD) pipelines will help maintain secure versions going forward.

Description

Wasmtime is a runtime for WebAssembly. In versions from 38.0.0 to before 38.0.3, the implementation of component-model related host-to-wasm trampolines in Wasmtime contained a bug where it's possible to carefully craft a component, which when called in a specific way, would crash the host with a segfault or assert failure. Wasmtime 38.0.3 has been released and is patched to fix this issue. There are no workarounds.

References

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