Varnish Enterprise

Known Issues

Known Issues

This page contains a list of issues with the current version of Varnish Enterprise, complementing the changelog which describes all released features and fixes in Varnish Enterprise 6.0.

The issues are organized by category or feature.


  • Clients making range requests can trigger a panic in MSE 4, unless mitigated through a VCL work-around: Unconditionally unset req.http.range in sub vcl_recv when using MSE 4. (VS issues 2197 and 2198)

    • This has been fixed in version 6.0.13r3.
  • If the child panics, the management process can go into an endless loop instead of successfully restarting the child.

    • This has been fixed in version 6.0.13r3.
  • Autodetection of io_uring capability does not work on Ubuntu 22.04 when using kernel image 5.15.0-112 (Linux kernel version 5.15.153).

    • This has been fixed in version 6.0.13r3. MSE4 will from this version correctly handle the bug present in kernel image 5.15.0-112 and fall back to classic AIO.
  • There is an issue with reference counting of Vary instruction slots, which can lead to an assert happening during Varnish daemon restarts. (VS issue #2209)

    • The assert message will look like: Assert error in mse4l_sm_vary_spec_delete(), mse4l_slotmachine_vary.c line 91: Condition(entry->slotidx != MSE4F_VARYIDX_NOVARY) not true.

    • This issue is fixed in version 6.0.13r4.