CVE-2026-120236 Details
Description
A vulnerability was detected in ag-ui-protocol ag-ui up to 0.0.58. Affected by this vulnerability is an unknown functionality of the component Transport Decoder Handler. The manipulation results in improper input validation. The attack may be launched remotely. The exploit is now public and may be used. The patch is identified as 660182b973a44b8eda5484b14b88eb9cc251edc4. It is suggested to upgrade the affected component.
A vulnerability exists in the AG-UI Protocol component Transport Decoder Handler, in versions through 0.0.58. This vulnerability allows for improper input validation, as events decoded from Protobuf are emitted without any schema validation. In contrast, events from an SSE stream are properly validated before being processed. This discrepancy can lead to downstream logic errors, as evidenced by a specific malformed event being accepted over Protobuf but rejected via SSE. The vulnerability can be exploited remotely, injecting type-confused or otherwise schema-invalid events directly into the client state machine, bypassing the intended validation and causing potential logic errors.
The vulnerability has been addressed in AG-UI version 1.0. Users are advised to upgrade to this version.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Nov 1, 2026CISA-ADP
Assessed Nov 2, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/ag-ui-protocol/ag-ui/ | [email protected] | Vendor |
| https://github.com/ag-ui-protocol/ag-ui/commit/660182b973a44b8eda5484b14b88eb9cc251edc4 | [email protected] | Source CodeVendor |
| https://github.com/ag-ui-protocol/ag-ui/issues/2524 | [email protected] | ExploitIssue TrackingTechnical DescriptionVendor |
| https://github.com/ag-ui-protocol/ag-ui/pull/2774 | [email protected] | Issue TrackingVendor |
| https://github.com/ag-ui-protocol/ag-ui/releases/tag/release/2026-10-30 | [email protected] | Release NotesVendor |
| https://vuldb.com/cve/CVE-2026-120236 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/submit/1015178 | [email protected] | Issue TrackingPermission Required |
| https://vuldb.com/vuln/429595 | [email protected] | AdvisoryPermission Required |
| https://vuldb.com/vuln/429595/cti | [email protected] | Content Wall |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| ag-ui-protocol ag-ui | <= 0.0.58 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Nov 2, 2026 | CVE Modified | CISA-ADP |
| Nov 1, 2026 | New CVE Received | [email protected] |