5.7

CVE-2026-34944: bytecodealliance wasmtime Uncaught Exception

CVSS: 5.7v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-34944DEBIAN-CVE-2026-34944CGA-45xj-4f6j-6x72
Published 09-04-2026Last modified 13-04-2026
Open JSON

Vulnerability summary

CVE-2026-34944 is a medium (CVSS 5.7) Uncaught Exception vulnerability in bytecodealliance wasmtime. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 16% of scored vulnerabilities.

Overall risk
23/100
0100
Low · default modelHow is this calculated?
CVSS score
5.7/10
010
Medium · v3.1 (NVD)
EPSS score
0.26%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-9GQP-P96H-8RJ6

Timeline

  1. 09-04-2026
    PublishedVulnerability first disclosed.
  2. 13-04-2026
    Last modifiedVulnerability information updated.

Description

Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, On x86-64 platforms with SSE3 disabled Wasmtime's compilation of the f64x2.splat WebAssembly instruction with Cranelift may load 8 more bytes than is necessary. When signals-based-traps are disabled this can result in a uncaught segfault due to loading from unmapped guard pages. With guard pages disabled it's possible for out-of-sandbox data to be loaded, but this data is not visible to WebAssembly guests. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.

CVSS metrics

9 scores · 7 sources · 2 versions

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

+0.03 pp

From 0.23% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.26%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard5 products
  • washAll versions (No fix recorded)
  • wasmcloud< 2.0.4-r0
  • wizer< 11.0.3-r10
  • yara-x< 1.15.0-r2
  • zed< 0.228.0-r3
Wolfi5 products
  • washAll versions (No fix recorded)
  • wasmcloud< 2.0.4-r0
  • wizer< 11.0.3-r10
  • yara-x< 1.15.0-r2
  • zed< 0.228.0-r3
Bytecodealliance1 product
  • wasmtime≥ 43.0.0, < 44.0.1 | < 24.0.7 | ≥ 25.0.0, < 36.0.7 | ≥ 37.0.0, < 42.0.2 | ≥ 43.0.0, < 43.0.1
Crates.Io1 product
  • wasmtime< 24.0.7 | ≥ 25.0.0, < 36.0.7 | ≥ 37.0.0, < 42.0.2 | ≥ 43.0.0, < 43.0.1
Debian1 product
  • rust-wasmtimeAll versions (No fix recorded) | < 36.0.7+dfsg-1
Ubuntu1 product
  • rust-wasmtimeAll versions (No fix recorded)

6 vendors · 14 products

References

10 links