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CVE-2026-115383VulnerabilityPublished Updated

Microsoft · Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via Tag Imports

Affects MicrosoftSource GCVE Database

0
Authoritative record:CVE-2026-115383· Medium 5.9

Not known to be exploited · CVSS 5.9 Medium : upgrade to 49.0.2 or 48.0.4 when convenient.

Data as of 28 Oct 2026, 09:43 UTC

CVSS 4.0 base score
5.9Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 49.0.2, 48.0.4
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Oct 2026

  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 wasmtime and github/bytecodealliance/wasmtime to 49.0.2 or 48.0.4.

Affected software

ProductAffectedFixed in
bytecodealliancewasmtimeAffected
  • >=49.0.0 <49.0.2
Fixed in
  • 49.0.2
bytecodealliancewasmtimeAffected
  • >=47.0.0 <48.0.4
Fixed in
  • 48.0.4
crates.iogithub/bytecodealliance/wasmtimepkg:cargo/github/bytecodealliance/wasmtimeOther threatsAffected
  • >=47.0.0 <48.0.4
  • >=49.0.0 <49.0.2
Fixed in
  • 48.0.4
  • 49.0.2
crates.iowasmtimepkg:cargo/wasmtimeOther threatsAffected
  • >=47.0.0 <48.0.4
  • >=49.0.0 <49.0.2
Fixed in
  • 48.0.4
  • 49.0.2

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

Description

CVE-2026-115383 is a vulnerability in Wasmtime versions 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 involving garbage collector (GC) heap corruption via tag imports. The advisory references Microsoft as the vendor but provides no detailed technical or impact information.

References

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