Commit: patch 9.2.0039: potential integer underflow in screen_line()

[Christian Brabandt]

patch 9.2.0039: potential integer underflow in screen_line()

Commit: https://github.com/vim/vim/commit/402eb5b5a6de2b16824eeefa7c4ef8cfd565a7d5
Author: Christian Brabandt <c...@256bit.org>
Date: Sat Feb 21 10:50:20 2026 +0000

patch 9.2.0039: potential integer underflow in screen_line()

Problem: In screen_line(), there is a potential integer underflow when
accessing ScreenAttrs[off_to - 1] if off_to is zero.
(Coverity CID 1681430, after v9.2.0017)
Solution: Add a check to ensure off_to > 0 before accessing the
previous attribute index.

related: #19272
closes: #19479

Signed-off-by: Christian Brabandt <c...@256bit.org>

diff --git a/src/screen.c b/src/screen.c
index 6e6f11b70..b3fe3705e 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -848,7 +848,7 @@ skip_opacity:
#ifdef FEAT_GUI
&& !gui.in_use
#endif
- && col + coloff > 0)
+ && col + coloff > 0 && off_to > 0)
{
if (ScreenAttrs[off_to] == ScreenAttrs[off_to - 1])
{
diff --git a/src/version.c b/src/version.c
index 871f3b239..336ac8894 100644
--- a/src/version.c
+++ b/src/version.c
@@ -734,6 +734,8 @@ static char *(features[]) =

static int included_patches[] =
{ /* Add new patch number below this line */
+/**/
+ 39,
/**/
38,
/**/