new file mode 100644
@@ -0,0 +1,49 @@
+From b024ae1749ee58c6fbf863b9a1f5dc440fee2e1b Mon Sep 17 00:00:00 2001
+From: Peter Harris <pharris2@rocketsoftware.com>
+Date: Thu, 15 Jan 2026 15:54:09 -0500
+Subject: [PATCH] xkb: fix buffer re-use in _XkbSetCompatMap
+
+If the "compat" buffer has previously been truncated, there will be
+unused space in the buffer. The code uses this space, but does not
+update the number of valid entries in the buffer.
+
+In the best case, this leads to the new compat entries being ignored. In the
+worst case, if there are any "skipped" compat entries, the number of
+valid entries will be corrupted, potentially leading to a buffer read
+overrun when processing a future request.
+
+Set the number of used "compat" entries when re-using previously
+allocated space in the buffer.
+
+CVE-2026-33999, ZDI-CAN-28593
+
+This vulnerability was discovered by:
+Jan-Niklas Sohn working with TrendAI Zero Day Initiative
+
+Signed-off-by: Peter Harris <pharris2@rocketsoftware.com>
+Acked-by: Olivier Fourdan <ofourdan@redhat.com>
+Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2176>
+
+Upstream-Status: Backport [https://gitlab.freedesktop.org/xorg/xserver/-/commit/b024ae1749ee58c6fbf863b9a1f5dc440fee2e1b]
+CVE: CVE-2026-33999
+Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
+---
+ xkb/xkb.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/xkb/xkb.c b/xkb/xkb.c
+index 137d70d..2b9004a 100644
+--- a/xkb/xkb.c
++++ b/xkb/xkb.c
+@@ -3004,7 +3004,7 @@ _XkbSetCompatMap(ClientPtr client, DeviceIntPtr dev,
+ return BadAlloc;
+ }
+ }
+- else if (req->truncateSI) {
++ else if (req->truncateSI || req->firstSI + req->nSI > compat->num_si) {
+ compat->num_si = req->firstSI + req->nSI;
+ }
+ sym = &compat->sym_interpret[req->firstSI];
+--
+2.43.0
+
@@ -35,6 +35,7 @@ SRC_URI = "https://www.x.org/archive/individual/xserver/xwayland-${PV}.tar.xz \
file://CVE-2025-62230-0001.patch \
file://CVE-2025-62230-0002.patch \
file://CVE-2025-62231.patch \
+ file://CVE-2026-33999.patch \
"
SRC_URI[sha256sum] = "33ec7ff2687a59faaa52b9b09aa8caf118e7ecb6aed8953f526a625ff9f4bd90"
Pick patch according to [2] [1] https://lists.x.org/archives/xorg-announce/2026-April/003679.html [2] https://security-tracker.debian.org/tracker/CVE-2026-33999 Signed-off-by: Vijay Anusuri <vanusuri@mvista.com> --- .../xwayland/xwayland/CVE-2026-33999.patch | 49 +++++++++++++++++++ .../xwayland/xwayland_23.2.5.bb | 1 + 2 files changed, 50 insertions(+) create mode 100644 meta/recipes-graphics/xwayland/xwayland/CVE-2026-33999.patch