How severe is CVE-2026-4964?

CVE-2026-4964 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2026-4964 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4964?

CVE-2026-4964 affects Letta. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4964?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-4964 have an EU (EUVD) identifier?

Yes. CVE-2026-4964 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16727.

When was CVE-2026-4964 published?

CVE-2026-4964 was published on 2026-03-27 and last updated on 2026-06-17.

CVE-2026-4964

CVE-2026-4964 is a medium-severity vulnerability in Letta with a CVSS 3.x base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: Medium (CVSS 3.x base score 6.3)
CVSS v2: 6.5
CVSS v4: 2.1
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-16727
Weakness: CWE-918
Affected product: Letta
Published: 2026-03-27
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-4964?: 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.
How severe is CVE-2026-4964?: CVE-2026-4964 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2026-4964 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4964?: CVE-2026-4964 affects Letta. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4964?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-4964 have an EU (EUVD) identifier?: Yes. CVE-2026-4964 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-16727.
When was CVE-2026-4964 published?: CVE-2026-4964 was published on 2026-03-27 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:letta:letta:0.16.4:*:*:*:*:*:*:*

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