From 457c8a00f9768c04acedd5f443445d20d6f0e95d Mon Sep 17 00:00:00 2001
From: pkgagent <pkgagent@tencent.com>
Date: Thu, 16 Apr 2026 11:14:53 +0800
Subject: [PATCH] fix CVE-2026-32853

---
 libvncserver-0.9.13-CVE-2026-32853.patch | 73 ++++++++++++++++++++++++
 libvncserver.spec                        |  7 ++-
 2 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 libvncserver-0.9.13-CVE-2026-32853.patch

diff --git a/libvncserver-0.9.13-CVE-2026-32853.patch b/libvncserver-0.9.13-CVE-2026-32853.patch
new file mode 100644
index 0000000..f487825
--- /dev/null
+++ b/libvncserver-0.9.13-CVE-2026-32853.patch
@@ -0,0 +1,73 @@
+From 009008e2f4d5a54dd71f422070df3af7b3dbc931 Mon Sep 17 00:00:00 2001
+From: Kazuma Matsumoto <269371721+y637F9QQ2x@users.noreply.github.com>
+Date: Sun, 22 Mar 2026 20:35:49 +0100
+Subject: [PATCH] libvncclient: add bounds checks to UltraZip subrectangle
+ parsing
+
+HandleUltraZipBPP() iterates over sub-rectangles using numCacheRects
+(derived from the attacker-controlled rect.r.x) without validating
+that the pointer stays within the decompressed data buffer. A malicious
+server can set a large numCacheRects value, causing heap out-of-bounds
+reads via the memcpy calls in the parsing loop.
+
+Add bounds checks before reading the 12-byte subrect header and before
+advancing the pointer by the raw pixel data size. Use uint64_t for the
+raw data size calculation to prevent integer overflow on 32-bit platforms.
+
+Adapted-by: PkgAgent (modified to adapt to opencloudos-stream)
+
+---
+ libvncclient/ultra.c |   16 +++++++++++++++-
+ 1 file changed, 15 insertions(+), 1 deletion(-)
+
+diff --git a/libvncclient/ultra.c b/libvncclient/ultra.c
+index a287526..56e2cd6 100644
+--- a/libvncclient/ultra.c
++++ b/libvncclient/ultra.c
+@@ -121,6 +121,7 @@ HandleUltraZipBPP (rfbClient* client, int rx, int ry, int rw, int rh)
+   int toRead=0;
+   int inflateResult=0;
+   unsigned char *ptr=NULL;
++  unsigned char *ptr_end=NULL;
+   lzo_uint uncompressedBytes = ry + (rw * 65535);
+   unsigned int numCacheRects = rx;
+ 
+@@ -184,11 +185,18 @@ HandleUltraZipBPP (rfbClient* client, int rx, int ry, int rw, int rh)
+   
+   /* Put the uncompressed contents of the update on the screen. */
+   ptr = (unsigned char *)client->raw_buffer;
++  ptr_end = ptr + uncompressedBytes;
+   for (i=0; i<numCacheRects; i++)
+   {
+     unsigned short sx, sy, sw, sh;
+     unsigned int se;
+ 
++    /* subrect header: sx(2) + sy(2) + sw(2) + sh(2) + se(4) = 12 bytes */
++    if (ptr + 12 > ptr_end) {
++      rfbClientLog("UltraZip: subrect %d header exceeds decompressed data bounds\n", i);
++      return FALSE;
++    }
++
+     memcpy((char *)&sx, ptr, 2); ptr += 2;
+     memcpy((char *)&sy, ptr, 2); ptr += 2;
+     memcpy((char *)&sw, ptr, 2); ptr += 2;
+@@ -203,8 +211,13 @@ HandleUltraZipBPP (rfbClient* client, int rx, int ry, int rw, int rh)
+ 
+     if (se == rfbEncodingRaw)
+     {
++        uint64_t rawBytes = (uint64_t)sw * sh * (BPP / 8);
++        if (rawBytes > (size_t)(ptr_end - ptr)) {
++          rfbClientLog("UltraZip: subrect %d raw data exceeds decompressed data bounds\n", i);
++          return FALSE;
++        }
+         client->GotBitmap(client, (unsigned char *)ptr, sx, sy, sw, sh);
+-        ptr += ((sw * sh) * (BPP / 8));
++        ptr += (size_t)rawBytes;
+     }
+   }  
+ 
+@@ -212,3 +225,4 @@ HandleUltraZipBPP (rfbClient* client, int rx, int ry, int rw, int rh)
+ }
+ 
+ #undef CARDBPP
++
diff --git a/libvncserver.spec b/libvncserver.spec
index 7c331ff..ab0d1e7 100644
--- a/libvncserver.spec
+++ b/libvncserver.spec
@@ -3,12 +3,13 @@
 Summary:   Library to make writing a VNC server easy
 Name:      libvncserver
 Version:   0.9.13
-Release:   8%{?dist}
+Release:   9%{?dist}
 License:   GPLv2+
 URL:       http://libvnc.github.io/
 Source0:   https://github.com/LibVNC/libvncserver/archive/LibVNCServer-%{version}.tar.gz
 
 Patch0001: CVE-2020-29260.patch
+Patch0002: libvncserver-0.9.13-CVE-2026-32853.patch
 
 Patch3000: 0001-libvncserver-Add-API-to-add-custom-I-O-entry-points.patch
 Patch3001: 0002-libvncserver-Add-channel-security-handlers.patch
@@ -64,6 +65,10 @@ rm -fv common/lzodefs.h common/lzoconf.h commmon/minilzo.h common/minilzo.c
 %{_libdir}/pkgconfig/libvncserver.pc
 
 %changelog
+* Thu Apr 16 2026 PkgAgent Robot <pkgagent@opencloudos.tech> - 0.9.13-9
+- [Type] security
+- [DESC] Fix CVE-2026-32853 vulnerability
+
 * Wed May 14 2025 cunshunxia <cunshunxia@tencent.com> - 0.9.13-8
 - fix CVE-2020-29260
 
-- 
Gitee