Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 Sandbox Escape via Symlink Rename
Summary
| CVE | CVE-2026-118688 |
|---|---|
| State | PUBLISHED |
| Assigner | VulnCheck |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-28 19:17:35 UTC |
| Updated | 2026-11-04 15:17:39 UTC |
| Description | wasmtime-wasi in Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 re-appends a trailing slash to rename source paths, causing renameat on macOS and FreeBSD hosts to follow directory symlinks. A guest with sandbox write access can rename a relative symlink such as "up/" to move host directories into its sandbox and read or write them. |
Risk And Classification
Primary CVSS: v4.0 8.8 HIGH from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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
EPSS: 0.002420000 probability, percentile 0.154900000 (date 2026-11-04)
Problem Types: CWE-61 | CWE-61 UNIX Symbolic Link (Symlink) Following
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 8.8 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/E:X/C... |
| 4.0 | CNA | CVSS | 8.8 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L |
| 3.1 | [email protected] | Secondary | 7.9 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L |
| 3.1 | CNA | CVSS | 7.9 | HIGH | CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
LowAttack Requirements
PresentPrivileges Required
LowUser Interaction
PassiveConfidentiality
HighIntegrity
HighAvailability
LowSub Conf.
HighSub Integrity
HighSub Availability
LowCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
LowUser Interaction
RequiredScope
ChangedConfidentiality
HighIntegrity
HighAvailability
LowCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Bytecodealliance | Wasmtime | affected 36.0.18 semver | Not specified |
| CNA | Bytecodealliance | Wasmtime | unaffected 36.0.18 semver | Not specified |
| CNA | Bytecodealliance | Wasmtime | affected 37.0.0 48.0.6 semver | Not specified |
| CNA | Bytecodealliance | Wasmtime | unaffected 48.0.6 semver | Not specified |
| CNA | Bytecodealliance | Wasmtime | affected 49.0.0 49.0.3 semver | Not specified |
| CNA | Bytecodealliance | Wasmtime | unaffected 49.0.3 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/bytecodealliance/wasmtime/security/advisories/GHSA-m9f7-9w4p-... | [email protected] | github.com | |
| www.vulncheck.com/advisories/wasmtime-before-36.0.18-37.0.0-before-48.0.6-and-4... | [email protected] | www.vulncheck.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: rvolosatovs (en)
CNA: alexcrichton (en)
There are currently no legacy QID mappings associated with this CVE.