keystone CVE-2026-40683 bullseye-security debdiff attached to #1133884

[James Montgomery <james_montgomery@disroot.org>]

Hello,

I prepared and tested a bullseye-security backport for keystone
CVE-2026-40683 and attached the debdiff to the existing BTS bug:

  https://bugs.debian.org/1133884

Validation included a successful pbuilder build in a bullseye chroot:

  sudo pbuilder build --use-network yes --distribution bullseye \
    --buildresult /tmp /tmp/keystone_18.1.0-1+deb11u3.dsc

I have not claimed the package in dla-needed.txt. This is provided as a
tested starting point if useful.

Regards,
James