CVE-2026-18990

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

• ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
• AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
• Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

0.40% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 32.8% of scored records. A rank, not a probability.

NVD base score

5.5 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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

NVD analysis status

Deferred. NVD last modified this record on 2026-08-12.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2026-08-06 02:15Z1 MO AGO

Last updated

2026-08-06 17:32Z29 DAYS AGO

Reserved

2026-08-05

Assigning CNA

VulDB

Record state

PUBLISHED

Severity

Medium (CVSS 6.9)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

Weaknesses

• CWE-287Improper AuthenticationClass
• CWE-306Missing Authentication for Critical FunctionBase

Data version

5.2

Document digest

94b6cf97e9f2070c7751589ec8d437b015af437b86f2268611d3845625c625e6

• vuldb.comVDB-386359 | letta-ai LettaBot API Status Route server.ts missing authenticationhttps://vuldb.com/vuln/386359vdb-entry
• vuldb.comVDB-386359 | CTI Indicators (IOB, IOC, IOA)https://vuldb.com/vuln/386359/ctisignaturepermissions-required
• vuldb.comCVE-2026-18990 | CVE Analysis and Reporthttps://vuldb.com/cve/CVE-2026-18990third-party-advisory
• vuldb.comSubmit #862562 | letta-ai LettaBot 0.2.0 Missing Authentication for Critical Function (CWE-306)https://vuldb.com/submit/862562third-party-advisory
• vuldb.comSubmit #862622 | letta-ai lettabot v0.2.0-alpha.13 Missing Authentication for Critical Function (CWE-306) (Duplicate)https://vuldb.com/submit/862622third-party-advisory
• gist.github.comhttps://gist.github.com/YLChen-007/2ba2e586f3d16cb368c8dcd6ef680178exploit