package/libssh2: fix CVE-2026-66032

Backport the fix for CVE-2026-66032.

A SFTP error path can leave a dangling pointer after freeing the
response buffer, which may result in a double free on subsequent error
handling.

Use Debian's libssh2 1.11.1 backport of the upstream fix.

Signed-off-by: Stefan Müller <stefan.mueller@rey-technology.com>
[Julien: add links to Debian patches]
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/libssh2/0007-sftp-prevent-dangling-pointer-after-free.patch

@@ -0,0 +1,29 @@
+From 5e4776146552d898b9c0e1b313cd093fa8dc92d0 Mon Sep 17 00:00:00 2001
+From: Will Cosgrove <will@panic.com>
+Date: Thu, 2 Jul 2026 11:00:23 -0700
+Subject: [PATCH] Prevent dangling pointer by nullifying data (#2180)
+
+Set data to NULL after freeing it to avoid dangling pointer. fixes
+GHSA-px3w-7g75-hg7w.
+
+Credit: VladimirEliTokarev
+Forwarded: not-needed
+
+CVE: CVE-2026-66032
+Upstream: https://sources.debian.org/patches/libssh2/1.11.1-6/CVE-2026-66032.patch/
+Upstream: https://github.com/libssh2/libssh2/commit/5e4776146552d898b9c0e1b313cd093fa8dc92d0
+Signed-off-by: Stefan Müller <stefan.mueller@rey-technology.com>
+---
+ src/sftp.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+--- a/src/sftp.c
++++ b/src/sftp.c
+@@ -1279,6 +1279,7 @@
+                                "got HANDLE FXOK"));
+
+                 LIBSSH2_FREE(session, data);
++                data = NULL;
+
+                 /* silly situation, but check for a HANDLE */
+                 rc = sftp_packet_require(sftp, SSH_FXP_HANDLE,

package/libssh2/libssh2.mk

@@ -27,6 +27,9 @@ LIBSSH2_IGNORE_CVES += CVE-2026-55200
 # 0006-sftp-symlink-fix-SSH_FXP_STATUS-response.patch
 LIBSSH2_IGNORE_CVES += CVE-2025-15661
 
+# 0007-sftp-prevent-dangling-pointer-after-free.patch
+LIBSSH2_IGNORE_CVES += CVE-2026-66032
+
 ifeq ($(BR2_PACKAGE_LIBSSH2_MBEDTLS),y)
 LIBSSH2_DEPENDENCIES += mbedtls
 LIBSSH2_CONF_OPTS += --with-libmbedcrypto-prefix=$(STAGING_DIR)/usr \