Depth counting error in guard() leading to multiple potential security issues in aioxmpp

Impact

Possible remote Denial of Service or Data Injection.

Patches

Patches are available in https://github.com/horazont/aioxmpp/pull/268. They have been backported to the 0.10 release series and 0.10.3 is the first release to contain the fix.

Workarounds

To make the bug exploitable, an error suppressing xso_error_handler is required. By not using xso_error_handlers or not using the suppression function, the vulnerability can be mitigated completely (to our knowledge).

References

The pull request contains a detailed description: https://github.com/horazont/aioxmpp/pull/268

For more information

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