diff --git a/meta-oe/recipes-devtools/yasm/yasm/CVE-2021-33464.patch b/meta-oe/recipes-devtools/yasm/yasm/CVE-2021-33464.patch
new file mode 100644
index 0000000000..ebae250ff9
--- /dev/null
+++ b/meta-oe/recipes-devtools/yasm/yasm/CVE-2021-33464.patch
@@ -0,0 +1,34 @@
+From 3c3f968d48d768c1e355199d4067d99cb72abc26 Mon Sep 17 00:00:00 2001
+From: Gyorgy Sarvari <skandigraun@gmail.com>
+Date: Sat, 15 Nov 2025 13:30:12 +0100
+Subject: [PATCH] Handle file descriptors with nonexisting env names better. 
+ Avoid writing past allocated memory.
+
+This fixes CVE-2021-33464.
+Author: Petter Reinholdtsen <pere@debian.org>
+Bug: https://github.com/yasm/yasm/issues/164
+Bug-Debian: https://bugs.debian.org/1016353
+Forwarded: https://github.com/yasm/yasm/issues/164
+Last-Update: 2025-04-30
+
+CVE: CVE-2021-33464
+Upstream-Status: Submitted [https://github.com/yasm/yasm/issues/164]
+
+Signed-off-by: Gyorgy Sarvari <skandigraun@gmail.com>
+---
+ modules/preprocs/nasm/nasm-pp.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/modules/preprocs/nasm/nasm-pp.c b/modules/preprocs/nasm/nasm-pp.c
+index 512f02c3..f9f92dd1 100644
+--- a/modules/preprocs/nasm/nasm-pp.c
++++ b/modules/preprocs/nasm/nasm-pp.c
+@@ -1815,7 +1815,7 @@ inc_fopen(char *file, char **newname)
+             error(ERR_WARNING, "environment variable `%s' does not exist",
+                   p1+1);
+             *p2 = '%';
+-            p1 = p2+1;
++            pb = p1 = p2+1;
+             continue;
+         }
+         /* need to expand */
diff --git a/meta-oe/recipes-devtools/yasm/yasm_git.bb b/meta-oe/recipes-devtools/yasm/yasm_git.bb
index bce62caadd..304fa0b34a 100644
--- a/meta-oe/recipes-devtools/yasm/yasm_git.bb
+++ b/meta-oe/recipes-devtools/yasm/yasm_git.bb
@@ -18,6 +18,7 @@ SRC_URI = "git://github.com/yasm/yasm.git;branch=master;protocol=https \
            file://0002-yasm-Use-BUILD_DATE-for-reproducibility.patch \
            file://CVE-2024-22653.patch \
            file://CVE-2023-29579.patch \
+           file://CVE-2021-33464.patch \
            "
 
 S = "${WORKDIR}/git"