CVE-2026-118688— 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

Quick assessment

Affected

bytecodealliance wasmtime

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Wasmtime 的以下版本中，存在安全漏洞：36.0.18 之前的版本、37.0.0 至 48.0.6 之前的版本，以及 49.0.0 至 49.0.3 之前的版本。该组件在处理重命名操作时，会重新在源路径末尾追加斜杠（），导致在 macOS 和 FreeBSD 主机上调用系统调用时，会跟随目录符号链接（symlink）。若沙箱内的 guest（沙箱内程序）拥有写权限，则可通过重命名相对符号链接（例如将重命名），将主机目录移入沙箱，进而对其进行读取或写入操作。

CVSS 7.9 · High EPSS 0.24% · P15 Updated Oct 29, 2026

Possible ATT&CK Techniques 2 AI

T1083 · File and Directory Discovery T1548.001 · Setuid and Setgid

Affected Version Matrix 6

Vendor	Product	Version Range	Status
bytecodealliance	wasmtime	`< 36.0.18`	affected
		`36.0.18`	unaffected
		`37.0.0< 48.0.6`	affected
		`48.0.6`	unaffected
		`49.0.0< 49.0.3`	affected
		`49.0.3`	unaffected

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Vulnerability Information

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Vulnerability Title

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

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:L

Source: CVE Program / CVE List V5

Vulnerability Type

CWE-61

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
bytecodealliance	wasmtime	0 ~ 36.0.18	-

II. Public POCs for CVE-2026-118688

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-118688

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Vendor Advisories for CVE-2026-118688 (2)

https://www.cve.org/CVERecord?id=CVE-2026-118688

IV. Related Vulnerabilities

Same product: wasmtime

Same vendor: bytecodealliance

Same weakness: CWE-61