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Fencer Intel
low 2.6

CVE-2026-115386 json

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 Memory Disclosure via fd_readdir

published last mo. modified 16d ago also EUVD-2026-108314 , GHSA-96f6-r43r-8c24 , RUSTSEC-2026-0323

cvss
2.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an information disclosure vulnerability in the WASIp1 fd_readdir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of leftover host stack or heap memory per directory entry.

Patch / fix

  • crates.io wasmtime-wasi 36.0.17, 48.0.4, 49.0.2
  • bytecodealliance wasmtime 36.0.17, 48.0.4, 49.0.2
  • rust-wasmtime Debian 14 36.0.20+dfsg-1

debian advisories DEBIAN-CVE-2026-115386

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-115386 updated cvss 3.3

wasmtime: wasmtime: Information disclosure via uninitialized struct padding in fd_readdir

  • Red Hat Connectivity Link 1 rhcl-1/wasm-shim-rhel9 Red Hat Enterprise Linux 10 tree-sitter 0.23.0-3.el10, virt-firmware-rs 26.4-1.el10
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
17d ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 4.0 2.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
CNA 3.1 2.6 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N
CNA 4.0 2.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected packages

ecosystem package affected fixed in
crates.io wasmtime-wasi
>=0.0.0-0, <36.0.17
>=37.0.0, <48.0.4
>=49.0.0, <49.0.2
36.0.17
48.0.4
49.0.2

Affected products

  • bytecodealliance wasmtime

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.