Recommended action

Update tornado to 6.5.6 if you use the affected versions. Test the change in a non-production environment first.

hol-guard supply-chain scan

What this means

Tornado has out-of-bounds memory access via C extension affects tornado (pip). Severity is medium. ### Summary Tornado's optional native extension `tornado.speedups` implements `websocket_mask` without validating that the `mask` argument is exactly four bytes long. The C function reads four bytes from `mask` unconditionally, even when Python passes a shorter byte string. This can read beyond the provided buffer, exposing up to 3 bytes of uninitialized memory. The behavior is reachable from Tornado's XSRF token decoder when `xsrf_cookies=True` and the native extension is active. ### Mitigations This bug is fixed in Tornado 6.5.6. Prior to upgrading to this version, setting the environment variable TORNADO_EXTENSION=0 will disable the vulnerable code (at the expense of reducing websocket performance).

AI coding agents often install or upgrade packages automatically in pip. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.

Affected software

Recommended action

Update tornado to 6.5.6 if you use the affected versions. Test the change in a non-production environment first.

hol-guard supply-chain scan

What this means

Tornado has out-of-bounds memory access via C extension affects tornado (pip). Severity is medium. ### Summary Tornado's optional native extension `tornado.speedups` implements `websocket_mask` without validating that the `mask` argument is exactly four bytes long. The C function reads four bytes from `mask` unconditionally, even when Python passes a shorter byte string. This can read beyond the provided buffer, exposing up to 3 bytes of uninitialized memory. The behavior is reachable from Tornado's XSRF token decoder when `xsrf_cookies=True` and the native extension is active. ### Mitigations This bug is fixed in Tornado 6.5.6. Prior to upgrading to this version, setting the environment variable TORNADO_EXTENSION=0 will disable the vulnerable code (at the expense of reducing websocket performance).

AI coding agents often install or upgrade packages automatically in pip. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.

Affected software