PT-2025-21340 · Wamr+1 · Wamr+1

Yagehu · Published 2025-05-15 · Updated 2025-09-19 · CVE-2025-43853

Positive Technologies (AI Summary)

CVSS v4.0

7.0

High

Base vector

AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N

Name of the Vulnerable Software and Affected Versions: WAMR versions up to and including 2.2.0 WAMR built with libc-uvwasi on Windows

Description: The issue is related to a symlink following vulnerability in the WebAssembly Micro Runtime (WAMR). On WAMR running in Windows, creating a symlink pointing outside of the preopened directory and subsequently opening it with create flag will create a file on the host outside of the sandbox. If the symlink points to an existing host file, it's also possible to open it and read its content.

Recommendations: For WAMR versions up to and including 2.2.0, update to version 2.3.0 to fix the issue. For WAMR built with libc-uvwasi on Windows, update to a version that does not use libc-uvwasi or apply a patch that fixes the symlink following vulnerability. As a temporary workaround, consider restricting the use of the create flag when opening files to minimize the risk of exploitation.

Exploit

Fix

Weakness Enumeration

CWE-61

Related Identifiers

CVE-2025-43853

GHSA-8FC8-4G25-C8M7

Affected Products

Wamr

Libc-Uvwasi

References · 8

• 🔥 https://github.com/bytecodealliance/wasm-micro-runtime/security/advisories/GHSA-8fc8-4g25-c8m7 · Exploit
• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/43xxx/CVE-2025-43853.json · Exploit
• https://github.com/bytecodealliance/wasm-micro-runtime/commit/28702edaf739cdeee54e81efe5868bf00724c33c · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2025-43853 · Security Note
• https://osv.dev/vulnerability/CVE-2025-43853 · Vendor Advisory
• https://t.me/cveNotify/135986 · Telegram Post
• https://twitter.com/CVEnew/status/1923073527894147215 · Twitter Post
• https://twitter.com/VulmonFeeds/status/1923112389475492253 · Twitter Post