---
id: "CVE-2026-118276"
kind: "vulnerability"
aliases: ["CVE-2026-118276"]
title: "a2ui web renderer expression parser lets remote input exhaust resources"
severity: "medium"
cvss: 4.0
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["a2ui", "javascript", "package", "typescript", "web-renderer"]
not_affected_if: ["not-using-a2ui-web-renderer"]
published_at: "2026-10-28T04:18:01+00:00"
first_seen_at: "2026-10-28T04:30:58+00:00"
updated_at: "2026-10-28T04:32:10+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118276", "first_seen_at": "2026-10-28T04:30:58+00:00"}]
---

# a2ui web renderer expression parser lets remote input exhaust resources

The formatString function in the a2ui web renderer's expression parser can be driven into heavy resource consumption by crafted input. An attacker who can send that input remotely can slow down or stall the rendering process.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed a2ui version and see whether it is `0.10.6` or earlier
- Check whether the web renderer's `renderers/web_core/src/v0_9/basic_catalog/expressions/expression_parser.ts` file contains the fix from commit `1f71d1aac1b145ef57c7526f9e0cff316f5934e2`

## Fix

- Apply patch commit `1f71d1aac1b145ef57c7526f9e0cff316f5934e2` to the a2ui web renderer
- Move to an a2ui release newer than `0.10.6` that includes this patch (exact release version unknown)

## Timeline

- 2026-10-28T04:30:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118276

## From the sources

A vulnerability was determined in a2ui-project a2ui up to 0.10.6. This vulnerability affects the function formatString of the file renderers/web_core/src/v0_9/basic_catalog/expressions/expression_parser.ts of the component Parser. This manipulation causes resource consumption. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized. Patch name: 1f71d1aac1b145ef57c7526f9e0cff316f5934e2. Applying a patch is the recommended action to fix this issue.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_