Cyber Resilience

CVE-2025-43853

Bytecodealliance Webassembly Micro Runtime ≤ 2.2.0

Public PoC
Published
15 May 2025
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v4 7.0
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/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
EPSS Score 0.0026 17th percentile
Risk Priority 33 floored blend · peak EPSS

Summary

CVE-2025-43853 is a high-severity UNIX Symbolic Link (Symlink) Following (CWE-61) vulnerability in Bytecodealliance Webassembly Micro Runtime. Its CVSS base score is 7.0 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 17th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

The WebAssembly Micro Runtime's (WAMR) iwasm package is the executable binary built with WAMR VMcore which supports WebAssembly System Interface (WASI) and command line interface. Anyone running WAMR up to and including version 2.2.0 or WAMR built with libc-uvwasi on…

more

Windows is affected by a symlink following vulnerability. 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 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. Version 2.3.0 fixes the issue.

CWE(s)
CWE-61

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-52284Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2023-48105Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2025-54126Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2025-64713Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2024-25431Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2024-34251Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2024-34250Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2025-58749Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2025-64704Same product: Bytecodealliance Webassembly Micro Runtime
CVE-2024-27532Same product: Bytecodealliance Webassembly Micro Runtime

Affected Assets

bytecodealliance
webassembly micro runtime
≤ 2.2.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 2 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V5.2.5

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement good match

Access enforcement must resolve the actual target of any file reference and apply authorizations to it, directly stopping symlink traversal to unauthorized objects.

AC-4 Information Flow Enforcement partial match

Information-flow enforcement on file operations must follow the resolved target rather than the link name, blocking unauthorized data movement via symlinks.

AC-6 Least Privilege partial match

Least-privilege restrictions on the directories that may contain links or targets reduce the set of files an attacker can reach even if a symlink is followed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent introduction of symlink-following flaws in file-handling code.

ID.RA-01 partial match
prevents

Vulnerability identification can discover existing symlink issues but does not prevent or remediate them in code.

PR.AA-05 partial match
prevents

Least-privilege access policies can limit damage from symlink attacks but do not address the coding flaw itself.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect symlink-following vulnerabilities before deployment, covering most of the weakness.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure-architecture principles require safe file-handling and canonicalization, directly addressing symlink attacks.

A.8.28 Secure coding partial match
prevents

Secure-coding standards mandate explicit symlink checks and safe open patterns, fully mitigating CWE-61.

A.8.3 Information access restriction partial match
mitigates

Access-control rules can restrict which files a process may open, reducing symlink-following risk but not eliminating the underlying path-resolution flaw.

A.8.9 Configuration management none match
none

Configuration management can enforce safe file-permission baselines that limit symlink abuse, but does not address the code flaw itself.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (1 rule)
  • V-248577 OL 8 must enable kernel parameters to enforce Discretionary Access Control (DAC) on symlinks. prevents CWE-61

References