Bun v1.3.10 panic: Illegal instruction at address 0x7FF6DB1634C0 on Windows 11 during Claude CLI usage (bundled Bun crash)

[IzmaIkhlaque]

What version of Bun is running?

1.3.10

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What steps can reproduce the bug?

1. Using Claude CLI (Anthropic's Claude Code / Claude CLI tool) — Bun is NOT installed separately by me; it's bundled inside the Claude CLI executable.
2. In an interactive Claude session, run commands that trigger tool execution (bash, python, MCP tools), such as:
   • "test it — search for all customers in Odoo"
   • "check" (to verify Odoo connection via python xmlrpc)
   • Other similar verification or tool-calling commands in sessions involving local Odoo instance and MCP setup.
3. The crash occurs repeatedly across different terminals/sessions, usually after some activity (e.g., multiple tool calls or longer session duration).
4. No custom user code is involved — it's during Claude CLI's normal operation / internal Bun usage.

What is the expected behavior?

Bun (bundled in Claude CLI) should execute the command/tool normally without crashing. The session should continue, and the output (e.g., Odoo search results or connection check) should be displayed as expected.

What do you see instead?

Bun crashes with an "Illegal instruction" panic. Examples from two separate occurrences:

Crash 1:
Elapsed: 378688ms | User: 149062ms | Sys: 41375ms
RSS: 1.43GB | Peak: 4.27GB | Commit: 9.74GB | Faults: 3569597 | Machine: 17.03GB
panic(main thread): Illegal instruction at address 0x7FF6DB1634C0
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.3.10/e_1d885ce7mgkgE+hogCgs6wtC600rtCw5/utC8rxrtCm7vrtCqh2wyCuhq8yC+in8yCssq7yCqs6llCkj4ozCy1m35C________A3s//Bh0ln9kB

Crash 2:
Elapsed: 617335ms | User: 118140ms | Sys: 28859ms
RSS: 6.22GB | Peak: 9.81GB | Commit: 10.90GB | Faults: 5637691 | Machine: 17.03GB
panic(thread 22204): Illegal instruction at address 0x7FF6DB1634C0
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
https://bun.report/1.3.10/e_1d885ce7mgkgE+hogCgs6wtC600rtCsgivtCkvxrtCm7vrtCog2y2B840y2Bk1k/6Bq/8znCs/v0iC2420iCwinx7Bykz71Cq3371Cgwg81Cgzhu3Bynhw2Bmp97vDCYKERNEL32.DLLut0LCSntdll.dll4gijBA3s//Bh0ln9kB

Additional information

• This crash ONLY happens inside Claude CLI (which bundles Bun v1.3.10) — I never use standalone Bun.
• Platform: Windows 11, location Hyderabad, Pakistan (if region/build matters).
• Crashes seem related to tool execution or longer sessions (high RSS: up to 6.22GB, Peak 9.81GB in logs).
• CPU detects avx/avx2, so not a basic missing-instruction issue — possibly baseline build bug, instruction selection, or allocator problem (similar to other Windows "Illegal instruction" reports like Crash - Illegal Instruction #24576, Illegal instruction at address 0x7ff7ccff5671, a core dump #10294, etc.).
• Workarounds tried: Restarting terminals, shorter sessions — still crashes during Claude tool use.
• Also reported to Anthropic support, as it's their bundled runtime.
• Happy to test canary builds, provide more logs, or help reproduce if needed.

Thanks!

[github-actions]

Found 3 possible duplicate issues:

1. Crash - Illegal Instruction #24576
2. [Windows] N-API vtable corruption causes segfault, TUI escape, and orphaned processes in Bun v1.3.10 #27471
3. Segmentation fault after long-running session on Windows (14h, 7GB peak RSS) #27525

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