Image blur GLSL

This question is not OpenGL specific but im using OpenGL as my API. I have tried to do blurring on hardware recently to implement bloom post-processing which succeeded except one point where the blurred image shows parts of the image on the opposite edges. Tried couple of things without success. For now my only idea was to increase the rendered fullscreen quad by some amount to make the edges invisible but maybe there is something im doing wrong with the blur? Basically im rendering the scene in a texture to a screen aligned quad blurring it and reading back the backbuffer rect to same texture with 4 iterations resulting in same image being blurred multiple times.
Any solutions are welcome.

The scene with increased blur iterations to show the problem (image bottom):

Looks like GL_REPEAT is involved in wrong place?

thanks for reply yooyo. it sounds like it though actually haven’t thought about it. GL_REPEAT is the default wrap value for all my textures, will try GL_CLAMP_TO_EDGE for this texture instead.

GL_CLAMP_TO_EDGE fixed it. thanks