CVE-2026-4964Public exploitNetwork attack vector

Authenticated server file read via ImageContent file URLs

Published Mar 27, 2026 · Updated Mar 27, 2026

SSRF in Letta 0.16.4 allows remote authenticated users to read server files by submitting a file URL in image content. The _convert_message_create_to_message and _resolve_url_to_base64 paths open the unvalidated file path, read its bytes, and base64-encode them. Ordinary API access is sufficient, and readable process files can expose server credentials and configuration.

CVSS severity6.5
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

SSRF in Letta 0.16.4 allows remote authenticated users to read server files by submitting a file URL in image content. The _convert_message_create_to_message and _resolve_url_to_base64 paths open the unvalidated file path, read its bytes, and base64-encode them. Ordinary API access is sufficient, and readable process files can expose server credentials and configuration.

The record

CVE
CVE-2026-4964
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
Letta
Product
Letta
Classifications
CWE-918, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.16.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Letta · Lettaversion=0.16.4

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P
2.1VulDBCVSS: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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)
T1005Data from Local System

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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