Dear Maintainer, I can confirm that the upstream patch from https://bugs.freedesktop.org/show_bug.cgi?id=103699 fixes both issues (plasma and firefox). Attaching a patch for debian.
Thank you, Robert
diff -u xorg-server-1.19.2/debian/changelog xorg-server-1.19.2/debian/changelog --- xorg-server-1.19.2/debian/changelog +++ xorg-server-1.19.2/debian/changelog @@ -1,3 +1,10 @@ +xorg-server (2:1.19.2-1+deb9u2.1) UNRELEASED; urgency=medium + + * glx: do not pick sRGB config for 32-bit RGBA visual + * upstream patch 2954b16c8730c7ed8441fd8dba25900f3aed265 + + -- Robert T. <r...@hq.sk> Wed, 12 Sep 2018 18:50:34 +0200 + xorg-server (2:1.19.2-1+deb9u2) stretch-security; urgency=high * Unvalidated extra length in ProcEstablishConnection (CVE-2017-12176) diff -u xorg-server-1.19.2/debian/patches/series xorg-server-1.19.2/debian/patches/series --- xorg-server-1.19.2/debian/patches/series +++ xorg-server-1.19.2/debian/patches/series @@ -11,0 +12 @@ +12_glx-Do-not-pick-sRGB-config-for-32b-RGBA-visual.diff only in patch2: unchanged: --- xorg-server-1.19.2.orig/debian/patches/12_glx-Do-not-pick-sRGB-config-for-32b-RGBA-visual.diff +++ xorg-server-1.19.2/debian/patches/12_glx-Do-not-pick-sRGB-config-for-32b-RGBA-visual.diff @@ -0,0 +1,16 @@ +Index: xorg-server-1.19.2/glx/glxscreens.c +=================================================================== +--- xorg-server-1.19.2.orig/glx/glxscreens.c ++++ xorg-server-1.19.2/glx/glxscreens.c +@@ -274,6 +274,11 @@ pickFBConfig(__GLXscreen * pGlxScreen, V + /* If it's the 32-bit RGBA visual, demand a 32-bit fbconfig. */ + if (visual->nplanes == 32 && config->rgbBits != 32) + continue; ++ /* If it's the 32-bit RGBA visual, do not pick sRGB capable config. ++ * This can cause issues with compositors that are not sRGB aware. ++ */ ++ if (visual->nplanes == 32 && config->sRGBCapable == GL_TRUE) ++ continue; + /* Can't use the same FBconfig for multiple X visuals. I think. */ + if (config->visualID != 0) + continue;
