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[scarthgap,1/5] xserver-xorg: Fix CVE-2026-33999

Message ID 20260512085923.820545-1-vanusuri@mvista.com
State New
Headers show
Series [scarthgap,1/5] xserver-xorg: Fix CVE-2026-33999 | expand

Commit Message

Vijay Anusuri May 12, 2026, 8:59 a.m. UTC 
Pick patch according to [1]

[1] https://lists.x.org/archives/xorg-announce/2026-April/003677.html
[2] https://security-tracker.debian.org/tracker/CVE-2026-33999

Signed-off-by: Vijay Anusuri <vanusuri@mvista.com>
---
 .../xserver-xorg/CVE-2026-33999.patch         | 49 +++++++++++++++++++
 .../xorg-xserver/xserver-xorg_21.1.18.bb      |  1 +
 2 files changed, 50 insertions(+)
 create mode 100644 meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2026-33999.patch
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Patch

diff --git a/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2026-33999.patch b/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2026-33999.patch
new file mode 100644
index 0000000000..cd3bf47397
--- /dev/null
+++ b/meta/recipes-graphics/xorg-xserver/xserver-xorg/CVE-2026-33999.patch
@@ -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
+
diff --git a/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.18.bb b/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.18.bb
index 7f6197a0b4..ef7f5c5bdb 100644
--- a/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.18.bb
+++ b/meta/recipes-graphics/xorg-xserver/xserver-xorg_21.1.18.bb
@@ -5,6 +5,7 @@  SRC_URI += "file://0001-xf86pciBus.c-use-Intel-ddx-only-for-pre-gen4-hardwar.pat
             file://0002-xkb-Make-the-RT_XKBCLIENT-resource-private.patch \
             file://0003-xkb-Free-the-XKB-resource-when-freeing-XkbInterest.patch \
             file://0004-xkb-Prevent-overflow-in-XkbSetCompatMap.patch \
+            file://CVE-2026-33999.patch \
             "
 SRC_URI[sha256sum] = "c878d1930d87725d4a5bf498c24f4be8130d5b2646a9fd0f2994deff90116352"