Frequent ERR_CONTENT_LENGTH_MISMATCH errors in browser console in dev environment

david · October 19, 2026, 10:58am

I found this, which includes some responses referencing Discourse:

github.com/microsoft/vscode-remote-release

net::ERR_CONTENT_LENGTH_MISMATCH returning large content when port-forwarding from devcontainer

opened 03:26PM - 11 Jun 24 UTC

closed 03:48PM - 15 Oct 26 UTC

rokos-angus

bug remote-explorer

Type: Bug VSCode 1.91.0-insider (reproducible with latest stable relea…se) Docker version 25.0.3, build 4debf41 (installed within WSL, not docker desktop) Run local devcontainer within WSL (ubuntu 22.04 image) Run any http webserver and port forward with vscode to windows host (I have best luck reproducing with flask python server) Access content from windows host browser. This seems to depend on the size of the content, most reliable when it is at least >100kb Expected Behavior Content is successfully displayed in the browser Actual Behavior Content appears to be truncated, browser logs Failed to load resource: net::ERR_CONTENT_LENGTH_MISMATCH It is worth noting that this issue does NOT happen when running and port forwarding the application in WSL directly, ONLY when running in a devcontainer Extension version: 0.372.0 VS Code version: Code - Insiders 1.91.0-insider (21decd9342dd2e14f2a7cd2883f84e6ff43ea0df, 2024-06-11T06:46:21.055Z) OS version: Windows_NT x64 10.0.22621 Modes: Remote OS version: Linux x64 5.15.146.1-microsoft-standard-WSL2 Remote OS version: Linux x64 5.15.146.1-microsoft-standard-WSL2 <details> <summary>System Info</summary> |Item|Value| |---|---| |CPUs|13th Gen Intel(R) Core(TM) i9-13900K (32 x 2995)| |GPU Status|2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled| |Load (avg)|undefined| |Memory (System)|127.76GB (68.02GB free)| |Process Argv|--crash-reporter-id 134e0632-6bb4-4424-ba75-d813c8e8d17a| |Screen Reader|no| |VM|0%| |Item|Value| |---|---| |Remote|Dev Container| |OS|Linux x64 5.15.146.1-microsoft-standard-WSL2| |CPUs|13th Gen Intel(R) Core(TM) i9-13900K (32 x 0)| |Memory (System)|62.68GB (56.87GB free)| |VM|0%| |Item|Value| |---|---| |Remote|WSL: Ubuntu| |OS|Linux x64 5.15.146.1-microsoft-standard-WSL2| |CPUs|13th Gen Intel(R) Core(TM) i9-13900K (32 x 0)| |Memory (System)|62.68GB (56.87GB free)| |VM|0%| </details><details> <summary>A/B Experiments</summary> ``` vsliv368:30146709 vspor879:30202332 vspor708:30202333 vspor363:30204092 vscod805cf:30301675 vsaa593cf:30376535 py29gd2263:31024238 c4g48928:30535728 2i9eh265:30646982 962ge761:30841072 pythongtdpath:30726887 welcomedialog:30812478 pythonidxpt:30768918 pythonnoceb:30776497 asynctok:30898717 dsvsc013:30777762 dsvsc014:30777825 dsvsc015:30821418 pythontestfixt:30866404 pythonregdiag2:30926734 pythonmypyd1:30859725 h48ei257:31000450 pythontbext0:30879054 accentitlementst:30870582 dsvsc016:30879898 dsvsc017:30880771 dsvsc018:30880772 cppperfnew:30980852 pythonait:30973460 jchc7451:31067543 showvideot:31016890 chatpanelt:31014475 g316j359:31013175 a69g1124:31018687 dvdeprecation:31040973 pythonprt:31036556 dwnewjupytercf:31046870 2f103344:31071589 nb_pri_only:31057983 fa862199:31048878 nativerepl1:31071684 ``` </details>

Seems like it might’ve been fixed via Prevent truncated responses through managed port-forwarding sockets - Pull Request #338875 - microsoft/vscode - GitHub, which was merged a few days ago. Should be live in the ‘insiders’ build of VSCode already

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Frequent ERR_CONTENT_LENGTH_MISMATCH errors in browser console in dev environment

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