Bug#1126591: libwebkit2gtk-4.1-0: [bookworm] Illegal Instruction at startup (SSE2 movq)

[Karo Gyoker]

Package: libwebkit2gtk-4.1-0
Version: 2.50.4-1~deb12u1
Severity: important
X-Debbugs-Cc: karogyoker2+debbug at gmail.com, team at security.debian.org

Dear Maintainer,

Since I did an apt update, epiphany-browser cannot start
due to illegal instruction (movq, which is part of SSE2).
I have an Athlon XP.

I can see in the git history that the SSE2 patch has been removed
because trixie requires SSE2, hence the patch is not needed anymore.
But I'm still on bookworm, and it still should work on bookworm.
Please, roll back the related git commits from 3 September 2025 in the
bookworm-security branch. Bookworm users without SSE2 should still have
a working browser until July 2028.

Thanks.

-- System Information:
Debian Release: 12.13
  APT prefers oldstable-updates
  APT policy: (500, 'oldstable-updates'), (500, 'oldstable-security'), (500, 'oldstable')
Architecture: i386 (i686)

Kernel: Linux 6.1.0-42-686-pae (SMP w/1 CPU thread; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages libwebkit2gtk-4.1-0 depends on:
ii  bubblewrap                      0.8.0-2+deb12u1
ii  gstreamer1.0-plugins-base       1.22.0-3+deb12u5
ii  gstreamer1.0-plugins-good       1.22.0-5+deb12u3
ii  libatk1.0-0                     2.46.0-5
ii  libatomic1                      12.2.0-14+deb12u1
ii  libavif15                       0.11.1-1+deb12u1
ii  libc6                           2.36-9+deb12u13
ii  libcairo-gobject2               1.16.0-7
ii  libcairo2                       1.16.0-7
ii  libdrm2                         2.4.114-1+b1
ii  libenchant-2-2                  2.3.3-2
ii  libepoxy0                       1.5.10-1
ii  libexpat1                       2.5.0-1+deb12u2
ii  libflite1                       2.2-5
ii  libfontconfig1                  2.14.1-4
ii  libfreetype6                    2.12.1+dfsg-5+deb12u4
ii  libgbm1                         22.3.6-1+deb12u1
ii  libgcc-s1                       12.2.0-14+deb12u1
ii  libgcrypt20                     1.10.1-3
ii  libgdk-pixbuf-2.0-0             2.42.10+dfsg-1+deb12u3
ii  libgles2                        1.6.0-1
ii  libglib2.0-0                    2.74.6-2+deb12u8
ii  libgpg-error0                   1.46-1
ii  libgstreamer-gl1.0-0            1.22.0-3+deb12u5
ii  libgstreamer-plugins-base1.0-0  1.22.0-3+deb12u5
ii  libgstreamer1.0-0               1.22.0-2+deb12u1
ii  libgtk-3-0                      3.24.38-2~deb12u3
ii  libharfbuzz-icu0                6.0.0+dfsg-3
ii  libharfbuzz0b                   6.0.0+dfsg-3
ii  libhyphen0                      2.8.8-7
ii  libicu72                        72.1-3+deb12u1
ii  libjavascriptcoregtk-4.1-0      2.50.4-1~deb12u1
ii  libjpeg62-turbo                 1:2.1.5-2
ii  liblcms2-2                      2.14-2
ii  libmanette-0.2-0                0.2.6-3+b1
ii  libpango-1.0-0                  1.50.12+ds-1
ii  libpangocairo-1.0-0             1.50.12+ds-1
ii  libpng16-16                     1.6.39-2+deb12u1
ii  libseccomp2                     2.5.4-1+deb12u1
ii  libsecret-1-0                   0.20.5-3
ii  libsoup-3.0-0                   3.2.3-0+deb12u2
ii  libsqlite3-0                    3.40.1-2+deb12u2
ii  libstdc++6                      12.2.0-14+deb12u1
ii  libsystemd0                     252.39-1~deb12u1
ii  libtasn1-6                      4.19.0-2+deb12u1
ii  libwayland-client0              1.21.0-1
ii  libwayland-egl1                 1.21.0-1
ii  libwayland-server0              1.21.0-1
ii  libwebp7                        1.2.4-0.2+deb12u1
ii  libwebpdemux2                   1.2.4-0.2+deb12u1
ii  libwebpmux3                     1.2.4-0.2+deb12u1
ii  libwoff1                        1.0.2-2
ii  libx11-6                        2:1.8.4-2+deb12u2
ii  libxml2                         2.9.14+dfsg-1.3~deb12u5
ii  libxslt1.1                      1.1.35-1+deb12u3
ii  xdg-dbus-proxy                  0.1.4-3
ii  zlib1g                          1:1.2.13.dfsg-1

Versions of packages libwebkit2gtk-4.1-0 recommends:
ii  gstreamer1.0-gl           1.22.0-3+deb12u5
ii  gstreamer1.0-libav        1.22.0-2
ii  gstreamer1.0-plugins-bad  1.22.0-4+deb12u6
ii  libgl1-mesa-dri           22.3.6-1+deb12u1
ii  xdg-desktop-portal-gtk    1.14.1-1

Versions of packages libwebkit2gtk-4.1-0 suggests:
pn  gstreamer1.0-alsa  <none>

-- no debconf information