Server-Side Request Forgery in letta by letta-ai
CVE-2026-4964

5.3MEDIUM

Key Information:

Vendor

Letta-ai

Status
Letta
Vendor
CVE Published:
27 March 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-4964?

A security flaw has been identified in the letta product by letta-ai, specifically in version 0.16.4. The vulnerability arises from the function _convert_message_create_to_message within the file letta/helpers/message_helper.py, which is part of the File URL Handler component. This flaw allows an attacker to manipulate the ImageContent argument, resulting in a server-side request forgery. Consequently, the vulnerability can be exploited remotely. Despite early disclosure to the vendor, there has been no response regarding remediation efforts. This exploit poses a significant risk, especially since it has been publicly disclosed and may be actively used by malicious actors.

Affected Version(s)

letta 0.16.4

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-4964 - Proof of Concept

References

https://vuldb.com/?id.353841
vdb-entrytechnical-description
https://vuldb.com/?ctiid.353841
signaturepermissions-required
https://vuldb.com/?submit.777645
third-party-advisory

CVSS V4

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Eric-z (VulDB User)
VulDB
.