diff --git a/hw-scsi-scsi-disk-MODE_PAGE_ALLS-not-allowed-in-MODE.patch b/hw-scsi-scsi-disk-MODE_PAGE_ALLS-not-allowed-in-MODE.patch
new file mode 100644
index 0000000..432e6cc
--- /dev/null
+++ b/hw-scsi-scsi-disk-MODE_PAGE_ALLS-not-allowed-in-MODE.patch
@@ -0,0 +1,50 @@
+From 08438d7975713bbeed2dff8467bd4656b34221ad Mon Sep 17 00:00:00 2001
+From: AlexChen <alex.chen@huawei.com>
+Date: Thu, 4 Nov 2021 17:31:38 +0100
+Subject: [PATCH] hw/scsi/scsi-disk: MODE_PAGE_ALLS not allowed in MODE SELECT
+ commands
+
+This avoids an off-by-one read of 'mode_sense_valid' buffer in
+hw/scsi/scsi-disk.c:mode_sense_page().
+
+Fixes: CVE-2021-3930
+Cc: qemu-stable@nongnu.org
+Reported-by: Alexander Bulekov <alxndr@bu.edu>
+Fixes: a8f4bbe2900 ("scsi-disk: store valid mode pages in a table")
+Fixes: #546
+Reported-by: Qiuhao Li <Qiuhao.Li@outlook.com>
+Signed-off-by: Mauro Matteo Cascella <mcascell@redhat.com>
+Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+cherry-pick from: b3af7fdf9cc537f8f0dd3e2423d83f5c99a457e8
+Signed-off-by: AlexChen <alex.chen@huawei.com>
+---
+ hw/scsi/scsi-disk.c | 6 ++++++
+ 1 file changed, 6 insertions(+)
+
+diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
+index cd90cd780e..297efd5a72 100644
+--- a/hw/scsi/scsi-disk.c
++++ b/hw/scsi/scsi-disk.c
+@@ -1082,6 +1082,7 @@ static int mode_sense_page(SCSIDiskState *s, int page, uint8_t **p_outbuf,
+     uint8_t *p = *p_outbuf + 2;
+     int length;
+
++    assert(page < ARRAY_SIZE(mode_sense_valid));
+     if ((mode_sense_valid[page] & (1 << s->qdev.type)) == 0) {
+         return -1;
+     }
+@@ -1423,6 +1424,11 @@ static int scsi_disk_check_mode_select(SCSIDiskState *s, int page,
+         return -1;
+     }
+
++    /* MODE_PAGE_ALLS is only valid for MODE SENSE commands */
++    if (page == MODE_PAGE_ALLS) {
++        return -1;
++    }
++
+     p = mode_current;
+     memset(mode_current, 0, inlen + 2);
+     len = mode_sense_page(s, page, &p, 0);
+--
+2.27.0
+