How severe is CVE-2025-43853?

CVE-2025-43853 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2025-43853 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-43853?

CVE-2025-43853 affects Bytecodealliance Webassembly Micro Runtime. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-43853?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-43853 have an EU (EUVD) identifier?

Yes. CVE-2025-43853 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-28017.

When was CVE-2025-43853 published?

CVE-2025-43853 was published on 2025-05-15 and last updated on 2026-06-17.

CVE-2025-43853

CVE-2025-43853 is a medium-severity vulnerability in Bytecodealliance Webassembly Micro Runtime with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-61.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v4: 7.0
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-28017
Weakness: CWE-61
Affected product: Bytecodealliance Webassembly Micro Runtime
Published: 2025-05-15
Last modified: 2026-06-17

Description

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 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.

Frequently asked questions

What is CVE-2025-43853?: 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 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.
How severe is CVE-2025-43853?: CVE-2025-43853 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2025-43853 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-43853?: CVE-2025-43853 affects Bytecodealliance Webassembly Micro Runtime. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-43853?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-43853 have an EU (EUVD) identifier?: Yes. CVE-2025-43853 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-28017.
When was CVE-2025-43853 published?: CVE-2025-43853 was published on 2025-05-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:bytecodealliance:webassembly_micro_runtime:*:*:*:*:*:*:*:*

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