EUVD-2026-80738
GHSA-wvf6-r87g-jh87
Severity by source
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:X/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
Network-reachable event processing (AV:N/AC:L), requires privileged/authenticated position in the event pipeline (PR:L), and a trust-boundary validation flaw yielding only limited C/I/A impact (all Low).
Primary rating from Vendor (VulDB).
CVSS VectorVendor: VulDB
Lifecycle Timeline
1DescriptionCVE.org
A weakness has been identified in ag-ui-protocol ag-ui 1.0. The impacted element is the function prepareRunAgentInput of the file agent/agent.ts of the component Event Application Layer. This manipulation of the argument TEXT_MESSAGE_START causes origin validation error. Remote exploitation of the attack is possible. The pull request to fix this issue awaits acceptance.
AnalysisAI
Origin validation errors in the AG-UI TypeScript client SDK (ag-ui 1.0) allow remote, low-privileged attackers who can influence an agent event stream to bypass event-origin checks and release the pending-interrupt gate, yielding low confidentiality, integrity, and availability impact. Affected deployments are those consuming untrusted or compromised AG-UI event sources; the advisory describes manipulation of the TEXT_MESSAGE_START argument, while the upstream fix PR #2701 also addresses an interrupt/resume state flaw where a stream emits an interrupt outcome and then finishes a subsequent run without a resume. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Requires the AG-UI TypeScript client SDK (@ag-ui/client, ag-ui 1.0) to process an attacker-influenced protocol event stream - specifically a sequence where a run emits an interrupt outcome and a subsequent run in the same stream finishes without a corresponding resume (per PR #2701), or a crafted TEXT_MESSAGE_START event that defeats origin validation (per the description). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | This is a medium-severity issue (vendor CVSS 4.0 base 5.3) with no signals of elevated real-world risk. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upstream fix available (PR/commit); released patched version not independently confirmed. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Unbounded memory growth in the AG-UI Rust client's SSE frame parser (crates/ag-ui-client/src/sse.rs, shipped in the ag-u
Unbounded memory growth in the ag-ui (AG-UI protocol) C++ community SDK's Server-Sent Events parser lets an attacker who
Memory exhaustion in the AG-UI Go community SDK's SSE client allows a remote attacker who controls or can intercept an S
A permissive cross-origin resource sharing (CORS) misconfiguration in the AG-UI aws-strands Python integration (ag-ui 0.
Same weakness CWE-346 – Origin Validation Error
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External POC / Exploit Code
Leaving vuln.today