From 39ce47f219b09c380b81f89fe54ac586c8db6bde Mon Sep 17 00:00:00 2001
From: Harry Sintonen <sintonen@iki.fi>
Date: Fri, 7 May 2021 13:09:57 +0200
Subject: [PATCH] telnet: check sscanf() for correct number of matches

CVE-2021-22898

Bug: https://curl.se/docs/CVE-2021-22898.html

Upstream-Status: Backport [https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde]

CVE: CVE-2021-22898

Signed-off-by: Harry Sintonen <sintonen@iki.fi>
Signed-off-by: Khairul Rohaizzat Jamaluddin <khairul.rohaizzat.jamaluddin@intel.com>
---
 lib/telnet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/telnet.c b/lib/telnet.c
index 26e0658ba9cc..fdd137fb0c04 100644
--- a/lib/telnet.c
+++ b/lib/telnet.c
@@ -922,7 +922,7 @@ static void suboption(struct Curl_easy *data)
         size_t tmplen = (strlen(v->data) + 1);
         /* Add the variable only if it fits */
         if(len + tmplen < (int)sizeof(temp)-6) {
-          if(sscanf(v->data, "%127[^,],%127s", varname, varval)) {
+          if(sscanf(v->data, "%127[^,],%127s", varname, varval) == 2) {
             msnprintf((char *)&temp[len], sizeof(temp) - len,
                       "%c%s%c%s", CURL_NEW_ENV_VAR, varname,
                       CURL_NEW_ENV_VALUE, varval);
