Escape sequence leaking to terminal on starting/attaching tmux (over ssh) #21875

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opened 2026-01-31 07:57:10 +00:00 by claunia · 0 comments
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Originally created by @plutonium-239 on GitHub (Jun 18, 2024).

Windows Terminal version

1.20.11381.0

Windows build number

10.0.19045.4529

Other Software

tmux (3.0a) over ssh (OpenSSH_for_Windows_9.1p1, LibreSSL 3.6.1)

Steps to reproduce

Log into ssh and attach/start a tmux session

Expected Behavior

Terminal is "clean" and only the prompt in a new tmux window is shown (if existing tmux then whatever contents were there before, unmodified).
The prompt is how you left it.

Actual Behavior

The escape sequence [?61;6;7;21;22;23;24;28;32;42c leaks to the terminal as input.
image
(Created a new tmux session) - this sequence is present at the beginning, with an extra ^[, and also in the input to the prompt.

Detaching from this and re-attaching adds this escape sequence to the prompt's input repeatedly in the active pane.

I found only these 2 threads that mention this exact sequence:

  1. wt issue #15693 relating to some problem in "NetDriver", does not seem related/I can't make sense of it
  2. wezterm issue which shows an identical problem but the issue did not see any resulting activity, just reproduction.
Additionally, here is a **debug tap** of creating a new session, starting with the `tmux` command:
␛[13;28;13;1;32;1_␛[m␍␊
␛[?2004l␛]0;[randomsshhostname]␣tmux␣~␇␛[13;28;13;0;32;1_␛[?1049h␛[22;0;0t␛[?1h␛=␛[2J␛[?12l␛[?1000l␛[?1002l␛[?1006l␛[?1005l␛[?1004h␛[?12;25h␛[?12l␛[?1003l␛[?1006l␛[?2004l␛[?1006h␛[?1002h␛[?25l␛[H␛[K␍␊
␛[K␍␊
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␣␛[38;2;224;222;244m␣0␣␣␛[38;2;144;140;170m␣␛[38;2;234;154;151mfish␣␛[38;2;246;193;119m0:fish*␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[38;2;156;207;216m17:32␣␛[38;2;144;140;170m␣󰃰␣␣␣␛[38;2;234;154;151mpluto␣␛[H␛[?25h␛[m^[[?61;6;7;21;22;23;24;28;32;42cWelcome␣to␣fish,␣the␣friendly␣interactive␣shell␍␊
Type␣␛[32mhelp␣␛[mfor␣instructions␣on␣how␣to␣use␣fish␍␊
␛[?2004h␛[?12l␛[?25l␛[H^[[?61;6;7;21;22;23;24;28;32;42cWelcome␣to␣fish,␣the␣friendly␣interactive␣shell␛[K␍␊
Type␣␛[32mhelp␣␛[mfor␣instructions␣on␣how␣to␣use␣fish␛[K␛[36m␍␊
⋊>␣pluto@randomsshhostname␣⋊>␣␛[33m~␣␛[m[?61;6;7;2␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[32m␛[1m(pluto)␣␛[90m␛[22m17:32:10␛[m␍␊
␛[K␍␊
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␛[K␍␊
␛[K␍␊
␛[K␛[38;2;62;143;176m␛[40m␍␊
␣␛[38;2;224;222;244m␣0␣␣␛[38;2;144;140;170m␣␛[38;2;234;154;151mfish␣␛[38;2;246;193;119m0:fish*␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[38;2;156;207;216m17:32␣␛[38;2;144;140;170m␣󰃰␣␣␣␛[38;2;234;154;151mpluto␣␛[3;38H␛[?25h␛[?25l␛[m␛[91m␛[3;28H[?61␛[32m;␛[91m6␛[32m;␛[91m7␛[32m;␛[91m21␛[32m;␛[91m22␛[32m;␛[91m23␛[32m;␛[91m24␛[32m;␛[91m28␛[32m;␛[91m32␛[32m;␛[91m42c␛[32m␛[1m␛[17C(pluto)␣␛[90m␛[22m17:32:10␛[3;58H␛[?25h␛[m␛[O

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Originally created by @plutonium-239 on GitHub (Jun 18, 2024). ### Windows Terminal version 1.20.11381.0 ### Windows build number 10.0.19045.4529 ### Other Software `tmux` (3.0a) over `ssh` (OpenSSH_for_Windows_9.1p1, LibreSSL 3.6.1) ### Steps to reproduce Log into ssh and attach/start a `tmux` session ### Expected Behavior Terminal is "clean" and only the prompt in a new tmux window is shown (if existing tmux then whatever contents were there before, unmodified). The prompt is how you left it. ### Actual Behavior The escape sequence `[?61;6;7;21;22;23;24;28;32;42c` leaks to the terminal as input. ![image](https://github.com/microsoft/terminal/assets/29684689/0141afe3-2401-41ce-89a5-a3535d7c7717) (Created a new tmux session) - this sequence is present at the beginning, with an extra `^[`, and also in the input to the prompt. Detaching from this and re-attaching adds this escape sequence to the prompt's input repeatedly in the active pane. I found only these 2 threads that mention this exact sequence: 1. wt issue #15693 relating to some problem in "NetDriver", does not seem related/I can't make sense of it 2. wezterm [issue](https://github.com/wez/wezterm/issues/4167) which shows an identical problem but the issue did not see any resulting activity, just reproduction. <details> <summary> Additionally, here is a **debug tap** of creating a new session, starting with the `tmux` command: </summary> ``` ␛[13;28;13;1;32;1_␛[m␍␊ ␛[?2004l␛]0;[randomsshhostname]␣tmux␣~␇␛[13;28;13;0;32;1_␛[?1049h␛[22;0;0t␛[?1h␛=␛[2J␛[?12l␛[?1000l␛[?1002l␛[?1006l␛[?1005l␛[?1004h␛[?12;25h␛[?12l␛[?1003l␛[?1006l␛[?2004l␛[?1006h␛[?1002h␛[?25l␛[H␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␛[H␛[?25h␛[?12l␛[?12;25h␛[?12l␛[?1003l␛[?1006l␛[?2004l␛[?1006h␛[?1002h␛[?12l␛[?25l␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␛[38;2;62;143;176m␛[40m␍␊ ␣␛[38;2;224;222;244m␣0␣␣␛[38;2;144;140;170m␣␛[38;2;234;154;151mfish␣␛[38;2;246;193;119m0:fish*␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[38;2;156;207;216m17:32␣␛[38;2;144;140;170m␣󰃰␣␣␣␛[38;2;234;154;151mpluto␣␛[H␛[?25h␛[m^[[?61;6;7;21;22;23;24;28;32;42cWelcome␣to␣fish,␣the␣friendly␣interactive␣shell␍␊ Type␣␛[32mhelp␣␛[mfor␣instructions␣on␣how␣to␣use␣fish␍␊ ␛[?2004h␛[?12l␛[?25l␛[H^[[?61;6;7;21;22;23;24;28;32;42cWelcome␣to␣fish,␣the␣friendly␣interactive␣shell␛[K␍␊ Type␣␛[32mhelp␣␛[mfor␣instructions␣on␣how␣to␣use␣fish␛[K␛[36m␍␊ ⋊>␣pluto@randomsshhostname␣⋊>␣␛[33m~␣␛[m[?61;6;7;2␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[32m␛[1m(pluto)␣␛[90m␛[22m17:32:10␛[m␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␍␊ ␛[K␛[38;2;62;143;176m␛[40m␍␊ ␣␛[38;2;224;222;244m␣0␣␣␛[38;2;144;140;170m␣␛[38;2;234;154;151mfish␣␛[38;2;246;193;119m0:fish*␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␣␛[K␛[38;2;156;207;216m17:32␣␛[38;2;144;140;170m␣󰃰␣␣␣␛[38;2;234;154;151mpluto␣␛[3;38H␛[?25h␛[?25l␛[m␛[91m␛[3;28H[?61␛[32m;␛[91m6␛[32m;␛[91m7␛[32m;␛[91m21␛[32m;␛[91m22␛[32m;␛[91m23␛[32m;␛[91m24␛[32m;␛[91m28␛[32m;␛[91m32␛[32m;␛[91m42c␛[32m␛[1m␛[17C(pluto)␣␛[90m␛[22m17:32:10␛[3;58H␛[?25h␛[m␛[O ``` ![image](https://github.com/microsoft/terminal/assets/29684689/1ec5b134-44ef-4f82-b67a-e52ee9b8afe4) </details>
claunia added the Needs-TriageIssue-Bug labels 2026-01-31 07:57:10 +00:00
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Reference: starred/terminal#21875