diff --git a/aide.spec b/aide.spec
index 3fc1ce86bf42d3b45d111965b94c6ccbe654214b..134ba464ab39fbd34132ac597b7b493c2df2dd6e 100644
--- a/aide.spec
+++ b/aide.spec
@@ -1,6 +1,6 @@
 Name:       aide
 Version:    0.17.3
-Release:    2
+Release:    3
 Summary:    Advanced Intrusion Detection Environment
 License:    GPLv2+
 URL:        http://sourceforge.net/projects/aide
@@ -8,6 +8,8 @@ Source0:    http://github.com/aide/aide/releases/download/v%{version}/%{name}-%{
 Source1:    aide.conf
 Source2:    aide.logrotate
 
+Patch0:     backport-CVE-2021-45417-Precalculate-buffer-size-in-base64-functions.patch
+
 BuildRequires:  gcc make bison flex pcre-devel libgpg-error-devel libgcrypt-devel zlib-devel libcurl-devel
 BuildRequires:  libacl-devel libselinux-devel libattr-devel e2fsprogs-devel audit-libs-devel
 
@@ -57,6 +59,12 @@ mkdir -p -m0700 %{buildroot}%{_localstatedir}/lib/aide
 %{_mandir}/*/*
 
 %changelog
+* Tue Feb 8 2022 yixiangzhike <yixiangzhike007@163.com> - 0.17.3-3
+- Type:CVE
+- ID:CVE-2021-45417
+- SUG:NA
+- DESC: fix CVE-2021-45417
+
 * Thu Aug 19 2021 yixiangzhike <zhangxingliang3@huawei.com> - 0.17.3-2
 - Type:bugfix
 - ID:NA
diff --git a/backport-CVE-2021-45417-Precalculate-buffer-size-in-base64-functions.patch b/backport-CVE-2021-45417-Precalculate-buffer-size-in-base64-functions.patch
new file mode 100644
index 0000000000000000000000000000000000000000..416ded00831cba2480405edc217e78f6ef10093f
--- /dev/null
+++ b/backport-CVE-2021-45417-Precalculate-buffer-size-in-base64-functions.patch
@@ -0,0 +1,146 @@
+From 9c3cc43f55f6b2935250932109eb23c60aaf1035 Mon Sep 17 00:00:00 2001
+From: Hannes von Haugwitz <hannes@vonhaugwitz.com>
+Date: Sat, 15 Jan 2022 17:16:51 +0100
+Subject: [PATCH] Precalculate buffer size in base64 functions
+
+Aide uses a fixed size (16k bytes) for the return buffer in
+encode_base64/decode_base64 functions. This results in a segfault if
+aide processes a file with too large extended attribute value or ACL.
+
+Fix this issue by precalculating the size of the return buffer depending on
+the input in the encode_base64/decode_base64 functions.
+
+This addresses CVE-2021-45417. Thanks to David Bouman for reporting this
+vulnerability and reviewing this patch.
+---
+ include/base64.h |  1 -
+ src/base64.c     | 35 +++++++++++++++++------------------
+ src/db.c         |  6 ++++--
+ 3 files changed, 21 insertions(+), 21 deletions(-)
+
+diff --git a/include/base64.h b/include/base64.h
+index a446812..d9cbfd2 100644
+--- a/include/base64.h
++++ b/include/base64.h
+@@ -35,7 +35,6 @@
+ #include <assert.h>
+ #include "types.h"
+ 
+-#define B64_BUF 16384
+ #define FAIL -1
+ #define SKIP -2
+ 
+diff --git a/src/base64.c b/src/base64.c
+index e01c0f5..09098db 100644
+--- a/src/base64.c
++++ b/src/base64.c
+@@ -85,11 +85,9 @@ FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL, FAIL
+ };
+ 
+ /* Returns NULL on error */
+-/* FIXME Possible buffer overflow on outputs larger than B64_BUF */
+ char* encode_base64(byte* src,size_t ssize)
+ {
+   char* outbuf;
+-  char* retbuf;
+   int pos;
+   int i, l, left;
+   unsigned long triple;
+@@ -100,7 +98,10 @@ char* encode_base64(byte* src,size_t ssize)
+     log_msg(LOG_LEVEL_DEBUG,"encode base64: empty string");
+     return NULL;
+   }
+-  outbuf = (char *)checked_malloc(sizeof(char)*B64_BUF);
++
++  /* length of encoded base64 string (padded) */
++  size_t length = sizeof(char)* ((ssize + 2) / 3) * 4;
++  outbuf = (char *)checked_malloc(length + 1);
+   
+   /* Initialize working pointers */
+   inb = src;
+@@ -161,20 +162,14 @@ char* encode_base64(byte* src,size_t ssize)
+       inb++;
+   }
+   
+-  /* outbuf is not completely used so we use retbuf */
+-  retbuf=(char*)checked_malloc(sizeof(char)*(pos+1));
+-  memcpy(retbuf,outbuf,pos);
+-  retbuf[pos]='\0';
+-  free(outbuf);
++  outbuf[pos]='\0';
+ 
+-  return retbuf;
++  return outbuf;
+ }
+ 
+-/* FIXME Possible buffer overflow on outputs larger than B64_BUF */
+ byte* decode_base64(char* src,size_t ssize, size_t *ret_len)
+ {
+   byte* outbuf;
+-  byte* retbuf;
+   char* inb;
+   int i;
+   int l;
+@@ -188,10 +183,18 @@ byte* decode_base64(char* src,size_t ssize, size_t *ret_len)
+     return NULL;
+   }
+ 
++  /* exit on unpadded input */
++  if (ssize % 4) {
++    log_msg(LOG_LEVEL_WARNING, "decode_base64: '%s' has invalid length (missing padding characters?)", src);
++    return NULL;
++  }
++
++  /* calculate length of decoded string, substract padding chars if any (ssize is >= 4) */
++  size_t length = sizeof(byte) * ((ssize / 4) * 3)- (src[ssize-1] == '=') - (src[ssize-2] == '=');
+ 
+   /* Initialize working pointers */
+   inb = src;
+-  outbuf = (byte *)checked_malloc(sizeof(byte)*B64_BUF);
++  outbuf = (byte *)checked_malloc(length + 1);
+ 
+   l = 0;
+   triple = 0;
+@@ -242,15 +245,11 @@ byte* decode_base64(char* src,size_t ssize, size_t *ret_len)
+       inb++;
+     }
+   
+-  retbuf=(byte*)checked_malloc(sizeof(byte)*(pos+1));
+-  memcpy(retbuf,outbuf,pos);
+-  retbuf[pos]='\0';
+-  
+-  free(outbuf);
++  outbuf[pos]='\0';
+ 
+   if (ret_len) *ret_len = pos;
+   
+-  return retbuf;
++  return outbuf;
+ }
+ 
+ size_t length_base64(char* src,size_t ssize)
+diff --git a/src/db.c b/src/db.c
+index d8b23a2..ac55f0a 100644
+--- a/src/db.c
++++ b/src/db.c
+@@ -428,13 +428,15 @@ db_line* db_char2line(char** ss, database* db){
+ 
+ time_t base64totime_t(char* s, database* db, const char* field_name){
+   
++  if(strcmp(s,"0")==0){
++      return 0;
++  }
+   byte* b=decode_base64(s,strlen(s),NULL);
+   char* endp;
+   
+-  if (b==NULL||strcmp(s,"0")==0) {
++  if (b==NULL) {
+     
+     /* Should we print error here? */
+-    free(b);
+     
+     return 0;
+   } else {
+-- 
+1.8.3.1
+