CVE-2026-4965: A vulnerability was detected in letta-ai letta 0.16.4

This week

HIGH 7.3REMOTEDOWNGRADE

CVE-2026-4965 is a high-severity flaw (CVSS 7.3) affecting letta. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability was detected in letta-ai letta 0.16.4. This issue affects the function resolve_type of the file letta/functions/ast_parsers.py of the component Incomplete Fix CVE-2025-6101. Performing a manipulation results in improper neutralization of directives in dynamically evaluated code. The attack can be initiated remotely. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-94, CWE-95
Published	2026-03-27
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: letta

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-27 18:16 UTCPublished CVE record published
2026-06-17 10:57 UTCUpdated Record last modified

letta letta DOWNGRADE

Affected: 0.16.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.16.4

1. Check installed version

apt-cache policy letta || rpm -q letta || letta --version

2. No fixed release: DOWNGRADE to a release before 0.16.4 (Debian / Ubuntu)

apt-cache madison letta sudo apt install letta=<VERSION_BEFORE_0.16.4> sudo apt-mark hold letta

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list letta sudo dnf downgrade letta-<VERSION_BEFORE_0.16.4> sudo dnf versionlock add letta

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-4965?

letta: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-4965 being exploited?

CVE-2026-4965 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-4965 affect?

CVE-2026-4965 affects letta. Severity is high (CVSS 7.3). A vulnerability was detected in letta-ai letta 0.16.4. This issue affects the function resolve_type of the file letta/functions/ast_parsers.py of the component Incomplete Fix CVE-2025-6101. Performing a manipulation results in improper neut

How urgent is CVE-2026-4965?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-4964 MEDIUM 6.3 DOWNGRADE A security vulnerability has been detected in letta-ai letta 0.16.4

References

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