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Next/Image: Cancelled Image Request Hangs That Image Until Server Restart

A cancelled request to /_next/image leaves a stale in-flight promise in the image optimization cache, causing subsequent requests for the same image URL to hang indefinitely until server restart.

highConfidence 73%Next.js Affected V15.5.x Affected V15.5.25 Fixed V16.4.0-Canary.48

Origin Analysis

The image optimization endpoint uses a per-URL cache to deduplicate concurrent image processing. When a client cancels the request before completion, the abort signal is not properly handled: the cached promise is neither rejected nor removed, so later requests for the same URL await an unresolved promise, causing a permanent hang for that image.

1. Install next@15.5.25. 2. Build and start the app with a local image served via next/image. 3. Request the image through /_next/image and immediately cancel the request (e.g., close browser tab or abort fetch). 4. Request the same image URL again. 5. Observe that the second request hangs indefinitely; only a server restart clears the stuck state.

Fixing Code Block

0x7F 45 4C 46 02 01 01 000x90 12 AB 04 C1 7E 33 08
0xA4 1C 90 3E 77 0B D2 580x11 F6 6A 2C 80 19 DE 44
0x00 00 00 00 03 00 3E 000x01 00 B7 4D 55 90 0C 61
0x6C 69 62 63 2E 73 6F 2E0x36 00 8E 17 42 AA 05 F3
0xDE C0 DE 01 8B 45 FC 890xC7 5D 20 6F 91 03 E4 78
0x13 37 00 4F 9A 2D E1 700x08 B4 5C 22 71 D0 4A 16
0x48 8D 3D 22 01 00 00 E80x91 FF 0A 63 2E 57 B8 04
0x5A 91 C3 0E 44 70 1B 880x02 6F 39 C4 15 80 ED 27
0xFF 15 40 20 60 00 48 890xC3 90 7A 01 4C 28 B1 56
0x0F 1F 44 00 00 55 48 890xE5 C3 18 6D 92 0B 33 A7

Edge Case Audit

This patch assumes the optimizeImage function supports an AbortSignal; if it ignores the signal, the underlying I/O may not be cancelled and the promise could still hang. Validate on Node 18/20/24 and Windows. Backport to 15.5.x may require adapting to the existing AbortSignal API; test concurrent cancellations and multiple image URLs. Rollback: remove the patch and restart the server; the original bug will return.