diff --git a/lib/IO/Stty.pm b/lib/IO/Stty.pm
index af61fb0..89f5d74 100644
--- a/lib/IO/Stty.pm
+++ b/lib/IO/Stty.pm
@@ -460,8 +460,10 @@ sub _parse_char_value {
         return hex($1);
     }
 
-    # Octal: 0 followed by digits (but not plain "0" which is decimal zero)
-    if ( $val =~ /^0(\d+)$/ ) {
+    # Octal: 0 followed by octal digits (0-7).  We deliberately exclude
+    # 8 and 9 so that inputs like "08" or "09" fall through to the decimal
+    # path instead of being silently truncated by oct().
+    if ( $val =~ /^0([0-7]+)$/ ) {
         return oct($1);
     }
 
diff --git a/t/01-parse-char-value.t b/t/01-parse-char-value.t
index 87e4e1b..f9d455a 100644
--- a/t/01-parse-char-value.t
+++ b/t/01-parse-char-value.t
@@ -45,6 +45,11 @@ my @tests = (
     [ '017',  15,   'octal 017' ],
     [ '0177', 127,  'octal 0177' ],
 
+    # Digits 8/9 after leading zero: NOT octal, treated as decimal
+    [ '08',   8,    '08 is decimal 8, not invalid octal' ],
+    [ '09',   9,    '09 is decimal 9, not invalid octal' ],
+    [ '019',  19,   '019 is decimal 19 (contains non-octal digit)' ],
+
     # undef / ^- (returns _POSIX_VDISABLE, which is 0 on Linux, 255 on macOS)
     [ 'undef', $VDISABLE, 'undef disables character (returns _POSIX_VDISABLE)' ],
     [ '^-',    $VDISABLE, '^- disables character (returns _POSIX_VDISABLE)' ],