curl: fix CVE-2025-9086

1, A cookie is set using the secure keyword for https://target
2, curl is redirected to or otherwise made to speak with http://target
(same hostname, but using clear text HTTP) using the same cookie set
3, The same cookie name is set - but with just a slash as path (path="/").
Since this site is not secure, the cookie should just be ignored.
4, A bug in the path comparison logic makes curl read outside a heap buffer boundary

The bug either causes a crash or it potentially makes the comparison come to
the wrong conclusion and lets the clear-text site override the contents of
the secure cookie, contrary to expectations and depending on the memory contents
immediately following the single-byte allocation that holds the path.

The presumed and correct behavior would be to plainly ignore the second set of
the cookie since it was already set as secure on a secure host so overriding
it on an insecure host should not be okay.

Reference:
https://nvd.nist.gov/vuln/detail/CVE-2025-9086

Upstream patch:
https://github.com/curl/curl/commit/c6ae07c6a541e0e96d0040afb6

(From OE-Core rev: dc842a631b178acd9c4f00c4a3b87831baf08ebb)

Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 56 insertions, 0 deletions

diff --git a/meta/recipes-support/curl/curl/CVE-2025-9086.patch b/meta/recipes-support/curl/curl/CVE-2025-9086.patch
new file mode 100644
index 0000000000..8ee7cd5192
--- /dev/null
+++ b/meta/recipes-support/curl/curl/CVE-2025-9086.patch
@@ -0,0 +1,55 @@
+From c6ae07c6a541e0e96d0040afb62b45dd37711300 Mon Sep 17 00:00:00 2001
+From: Daniel Stenberg <daniel@haxx.se>
+Date: Mon, 11 Aug 2025 20:23:05 +0200
+Subject: [PATCH] cookie: don't treat the leading slash as trailing
+
+If there is only a leading slash in the path, keep that. Also add an
+assert to make sure the path is never blank.
+
+Reported-by: Google Big Sleep
+Closes #18266
+
+CVE: CVE-2025-9086
+Upstream-Status: Backport [https://github.com/curl/curl/commit/c6ae07c6a541e0e96d0040afb6]
+
+Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
+---
+ lib/cookie.c | 9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+diff --git a/lib/cookie.c b/lib/cookie.c
+index e287458..ac7d3de 100644
+--- a/lib/cookie.c
++++ b/lib/cookie.c
+@@ -312,7 +312,7 @@ static char *sanitize_cookie_path(const char *cookie_path)
+   }
+
+   /* convert /hoge/ to /hoge */
+-  if(len && new_path[len - 1] == '/') {
++  if(len > 1 && new_path[len - 1] == '/') {
+     new_path[len - 1] = 0x0;
+   }
+
+@@ -1078,7 +1078,7 @@ Curl_cookie_add(struct Curl_easy *data,
+         if(clist->spath && co->spath) {
+           if(clist->secure && !co->secure && !secure) {
+             size_t cllen;
+-            const char *sep;
++            const char *sep = NULL;
+
+             /*
+              * A non-secure cookie may not overlay an existing secure cookie.
+@@ -1087,8 +1087,9 @@ Curl_cookie_add(struct Curl_easy *data,
+              * "/loginhelper" is ok.
+              */
+
+-            sep = strchr(clist->spath + 1, '/');
+-
++            DEBUGASSERT(clist->spath[0]);
++            if(clist->spath[0])
++              sep = strchr(clist->spath + 1, '/');
+             if(sep)
+               cllen = sep - clist->spath;
+             else
+--
+2.40.0
diff --git a/meta/recipes-support/curl/curl_7.82.0.bb b/meta/recipes-support/curl/curl_7.82.0.bb
index 623d8a4bc3..54362e6978 100644
--- a/meta/recipes-support/curl/curl_7.82.0.bb
+++ b/meta/recipes-support/curl/curl_7.82.0.bb
@@ -66,6 +66,7 @@ SRC_URI = "https://curl.se/download/${BP}.tar.xz \
            file://CVE-2024-11053-0001.patch \
            file://CVE-2024-11053-0002.patch \
            file://CVE-2025-0167.patch \
+           file://CVE-2025-9086.patch \
            "
 SRC_URI[sha256sum] = "0aaa12d7bd04b0966254f2703ce80dd5c38dbbd76af0297d3d690cdce58a583c"