Cyber Resilience

CVE-2026-4964

Medium

Published: 27 March 2026

Published
27 March 2026
Modified
30 March 2026
KEV Added
—
Patch
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CVSS Score v4 5.3 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0033 24.5th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-4964 is a medium-severity SSRF (CWE-918) vulnerability. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 24.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Supply Chain and Deployment risk domain.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)
CWE-918

AI Security AnalysisAI

AI Category
AI Agent Protocols and Integrations
Risk Domain
Supply Chain and Deployment
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: ai

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1552.005 Cloud Instance Metadata API Credential Access
Adversaries may attempt to access the Cloud Instance Metadata API to collect credentials and other sensitive data.
attack.mitre.org →
Why these techniques?

SSRF in public-facing File URL Handler directly enables remote exploitation of the application (T1190) and common SSRF abuse to query cloud instance metadata APIs (T1522).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

Affected Assets

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

SC-7 Boundary Protection
addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

SI-10 Information Input Validation
addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

SI-4 System Monitoring
addresses: CWE-918

Detects server-side request forgery through monitoring of unexpected outbound connections.

References