Vulnerabilities · 6h ago

Next.js ImageResponse Flaw Exposes Server Code Execution

Vercel fixed CVE-2026-94545 in Next.js 16.3.6 after finding that attacker-controlled values in ImageResponse could be interpreted as SVG on the default Node.js runtime, creating a path to server-side code execution. The issue affects Next.js 16.2.0 through 16.3.5; Next.js 15 and the Edge runtime are not affected.

ImageResponse uses Satori to turn layout into SVG before producing the final image. If request-derived text is allowed into SVG content, attributes, or styles, the renderer can treat it as structure instead of plain text, so a feature meant for previews can reach the server process with attacker influence.

For teams using next/og or route handlers that reflect request input, the exposure sits in the rendering layer, not in the image file itself. The remaining question is which deployments actually pass user-controlled values into that SVG path, because that is what turns a formatting feature into a code-execution risk.

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Part of the PlainSec briefing for 2026-10-01

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