diff --git a/ChangeLog.md b/ChangeLog.md
index 8293dd0..034fd23 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -120,6 +120,12 @@
 erroneously call `tjCompress*()` or `tjTransform()` with a reused JPEG
 destination buffer pointer while specifying a destination buffer size of 0.
 
+19. Hardened the libjpeg API against hypothetical applications that may
+erroneously set one of the exposed quantization table values to 0 just before
+calling `jpeg_start_compress()`.  (This would never happen in a
+correctly-written program, because `jpeg_add_quant_table()` clamps all values
+less than 1.)
+
 
 2.0.8 ESR
 =========
diff --git a/jcdctmgr.c b/jcdctmgr.c
index c04058e..08ddc75 100644
--- a/jcdctmgr.c
+++ b/jcdctmgr.c
@@ -6,7 +6,7 @@
  * libjpeg-turbo Modifications:
  * Copyright (C) 1999-2006, MIYASAKA Masaru.
  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2011, 2014-2015, D. R. Commander.
+ * Copyright (C) 2011, 2014-2015, 2026, D. R. Commander.
  * For conditions of distribution and use, see the accompanying README.ijg
  * file.
  *
@@ -176,11 +176,17 @@
   UDCTELEM c;
   int b, r;
 
-  if (divisor == 1) {
+  if (divisor <= 1) {
     /* divisor == 1 means unquantized, so these reciprocal/correction/shift
      * values will cause the C quantization algorithm to act like the
      * identity function.  Since only the C quantization algorithm is used in
      * these cases, the scale value is irrelevant.
+     *
+     * divisor == 0 can never happen in a normal program, because
+     * jpeg_add_quant_table() clamps values < 1.  However, a program could
+     * abuse the API by manually modifying the exposed quantization table just
+     * before calling jpeg_start_compress().  Thus, we effectively clamp
+     * values < 1 here as well, to avoid dividing by 0.
      */
     dtbl[DCTSIZE2 * 0] = (DCTELEM)1;                        /* reciprocal */
     dtbl[DCTSIZE2 * 1] = (DCTELEM)0;                        /* correction */