new file mode 100644
@@ -0,0 +1,375 @@
+From c1cfdf59acbaf9504c4578d4cf56cdd7c8594507 Mon Sep 17 00:00:00 2001
+From: Daniel Stenberg <daniel@haxx.se>
+Date: Mon, 27 Apr 2026 09:14:51 +0200
+Subject: [PATCH] setopt: clear proxy auth properties when switching
+
+Verify with test 1588
+
+Closes #21453
+
+CVE: CVE-2026-7168
+Upstream-Status: Backport [https://github.com/curl/curl/commit/c1cfdf59acbaf9504c4578d4cf56cdd7c8594507]
+
+Backport Changes:
+- Adapted setproxy() insertion and test-list placement to the curl 8.19.0 wrynose layout.
+
+(cherry picked from commit c1cfdf59acbaf9504c4578d4cf56cdd7c8594507)
+Signed-off-by: Anil Dongare <adongare@cisco.com>
+---
+ lib/setopt.c | 14 +++-
+ lib/vauth/vauth.h | 1 +
+ tests/data/Makefile.am | 2 +-
+ tests/data/test1588 | 106 ++++++++++++++++++++++++++
+ tests/libtest/Makefile.inc | 2 +-
+ tests/libtest/lib1588.c | 150 +++++++++++++++++++++++++++++++++++++
+ 6 files changed, 272 insertions(+), 3 deletions(-)
+ create mode 100644 tests/data/test1588
+ create mode 100644 tests/libtest/lib1588.c
+
+diff --git a/lib/setopt.c b/lib/setopt.c
+index 84f3e02..d12ffb6 100644
+--- a/lib/setopt.c
++++ b/lib/setopt.c
+@@ -49,6 +49,7 @@
+ #include "curlx/strdup.h"
+ #include "escape.h"
+ #include "bufref.h"
++#include "vauth/vauth.h"
+
+ static CURLcode setopt_set_timeout_sec(timediff_t *ptimeout_ms, long secs)
+ {
+@@ -1664,6 +1665,17 @@ static CURLcode cookiefile(struct Curl_easy *data, const char *ptr)
+ #endif
+
+ #ifndef CURL_DISABLE_PROXY
++static CURLcode setproxy(struct Curl_easy *data, const char *proxy)
++{
++ if((data->set.str[STRING_PROXY] && proxy) &&
++ !strcmp(data->set.str[STRING_PROXY], proxy))
++ return CURLE_OK;
++
++ Curl_auth_digest_cleanup(&data->state.proxydigest);
++ memset(&data->state.authproxy, 0, sizeof(data->state.authproxy));
++ return Curl_setstropt(&data->set.str[STRING_PROXY], proxy);
++}
++
+ static CURLcode setopt_cptr_proxy(struct Curl_easy *data, CURLoption option,
+ const char *ptr)
+ {
+@@ -1759,7 +1771,7 @@ static CURLcode setopt_cptr_proxy(struct Curl_easy *data, CURLoption option,
+ * Setting it to NULL, means no proxy but allows the environment variables
+ * to decide for us (if CURLOPT_SOCKS_PROXY setting it to NULL).
+ */
+- return Curl_setstropt(&s->str[STRING_PROXY], ptr);
++ return setproxy(data, ptr);
+ case CURLOPT_PRE_PROXY:
+ /*
+ * Set proxy server:port to use as SOCKS proxy.
+diff --git a/lib/vauth/vauth.h b/lib/vauth/vauth.h
+index 3e66c89..20ee51e 100644
+--- a/lib/vauth/vauth.h
++++ b/lib/vauth/vauth.h
+@@ -117,6 +117,7 @@ CURLcode Curl_auth_create_digest_http_message(struct Curl_easy *data,
+ /* This is used to clean up the digest specific data */
+ void Curl_auth_digest_cleanup(struct digestdata *digest);
+ #else
++#define Curl_auth_digest_cleanup(x)
+ #define Curl_auth_is_digest_supported() FALSE
+ #endif /* !CURL_DISABLE_DIGEST_AUTH */
+
+diff --git a/tests/data/Makefile.am b/tests/data/Makefile.am
+index 1b76b01..1e84b26 100644
+--- a/tests/data/Makefile.am
++++ b/tests/data/Makefile.am
+@@ -208,7 +208,7 @@ test1548 test1549 test1550 test1551 test1552 test1553 test1554 test1555 \
+ test1556 test1557 test1558 test1559 test1560 test1561 test1562 test1563 \
+ test1564 test1565 test1566 test1567 test1568 test1569 test1570 test1571 \
+ test1572 test1573 test1574 test1575 test1576 test1577 test1578 test1579 \
+-test1580 test1581 test1582 test1583 test1584 test1585 \
++test1580 test1581 test1582 test1583 test1584 test1585 test1588 \
+ \
+ test1590 test1591 test1592 test1593 test1594 test1595 test1596 test1597 \
+ test1598 test1599 test1600 test1601 test1602 test1603 test1604 test1605 \
+diff --git a/tests/data/test1588 b/tests/data/test1588
+new file mode 100644
+index 0000000..753e98c
+--- /dev/null
++++ b/tests/data/test1588
+@@ -0,0 +1,106 @@
++<?xml version="1.0" encoding="US-ASCII"?>
++<testcase>
++<info>
++<keywords>
++HTTP
++HTTP GET
++HTTP proxy
++HTTP proxy Digest auth
++multi
++</keywords>
++</info>
++
++# Server-side
++<reply>
++
++# this is returned first since we get no proxy-auth
++<data crlf="headers">
++HTTP/1.1 407 Authorization Required to proxy me my dear
++Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"
++Content-Length: 33
++
++And you should ignore this data.
++</data>
++
++# then this is returned when we get proxy-auth
++<data1000 crlf="headers">
++HTTP/1.1 200 OK
++Content-Length: 21
++Server: no
++
++Nice proxy auth sir!
++</data1000>
++
++<datacheck crlf="headers">
++HTTP/1.1 407 Authorization Required to proxy me my dear
++Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"
++Content-Length: 33
++
++HTTP/1.1 200 OK
++Content-Length: 21
++Server: no
++
++Nice proxy auth sir!
++HTTP/1.1 407 Authorization Required to proxy me my dear
++Proxy-Authenticate: Digest realm="weirdorealm", nonce="12345"
++Content-Length: 33
++
++HTTP/1.1 200 OK
++Content-Length: 21
++Server: no
++
++Nice proxy auth sir!
++</datacheck>
++</reply>
++
++# Client-side
++<client>
++<server>
++http
++</server>
++# tool is what to use instead of 'curl'
++<tool>
++lib%TESTNUMBER
++</tool>
++<features>
++!SSPI
++crypto
++proxy
++digest
++</features>
++<name>
++HTTP proxy auth Digest, then change proxy and do it again
++</name>
++<command>
++http://test.remote.example.com/path/%TESTNUMBER %HOSTIP %HTTPPORT silly:person custom.set.host.name
++</command>
++</client>
++
++# Verify data after the test has been "shot"
++<verify>
++<protocol crlf="headers">
++GET http://test.remote.example.com/path/1588 HTTP/1.1
++Host: test.remote.example.com
++Accept: */*
++Proxy-Connection: Keep-Alive
++
++GET http://test.remote.example.com/path/1588 HTTP/1.1
++Host: test.remote.example.com
++Proxy-Authorization: Digest username="silly", realm="weirdorealm", nonce="12345", uri="/path/1588", response="d0b2f000c7e3fca24452b5810713404a"
++Accept: */*
++Proxy-Connection: Keep-Alive
++
++GET http://test.remote.example.com/path/1588 HTTP/1.1
++Host: test.remote.example.com
++Accept: */*
++Proxy-Connection: Keep-Alive
++
++GET http://test.remote.example.com/path/1588 HTTP/1.1
++Host: test.remote.example.com
++Proxy-Authorization: Digest username="silly", realm="weirdorealm", nonce="12345", uri="/path/1588", response="d0b2f000c7e3fca24452b5810713404a"
++Accept: */*
++Proxy-Connection: Keep-Alive
++
++</protocol>
++</verify>
++</testcase>
+diff --git a/tests/libtest/Makefile.inc b/tests/libtest/Makefile.inc
+index 2f77c16..96b82bc 100644
+--- a/tests/libtest/Makefile.inc
++++ b/tests/libtest/Makefile.inc
+@@ -97,7 +97,7 @@ TESTS_C = \
+ lib1559.c lib1560.c lib1564.c lib1565.c \
+ lib1567.c lib1568.c lib1569.c lib1571.c \
+ lib1576.c \
+- lib1582.c \
++ lib1582.c lib1588.c \
+ lib1591.c lib1592.c lib1593.c lib1594.c lib1597.c \
+ lib1598.c lib1599.c \
+ lib1662.c \
+diff --git a/tests/libtest/lib1588.c b/tests/libtest/lib1588.c
+new file mode 100644
+index 0000000..9b12f36
+--- /dev/null
++++ b/tests/libtest/lib1588.c
+@@ -0,0 +1,150 @@
++/***************************************************************************
++ * _ _ ____ _
++ * Project ___| | | | _ \| |
++ * / __| | | | |_) | |
++ * | (__| |_| | _ <| |___
++ * \___|\___/|_| \_\_____|
++ *
++ * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
++ *
++ * This software is licensed as described in the file COPYING, which
++ * you should have received as part of this distribution. The terms
++ * are also available at https://curl.se/docs/copyright.html.
++ *
++ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
++ * copies of the Software, and permit persons to whom the Software is
++ * furnished to do so, under the terms of the COPYING file.
++ *
++ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
++ * KIND, either express or implied.
++ *
++ * SPDX-License-Identifier: curl
++ *
++ ***************************************************************************/
++/*
++ * argv1 = URL
++ * argv2 = proxy host
++ * argv3 = proxy port
++ * argv4 = proxyuser:password
++ */
++
++#include "first.h"
++
++static CURLcode init1588(CURL *curl, const char *url,
++ const char *userpwd, const char *proxy)
++{
++ CURLcode result = CURLE_OK;
++
++ res_easy_setopt(curl, CURLOPT_URL, url);
++ if(result)
++ goto init_failed;
++
++ res_easy_setopt(curl, CURLOPT_PROXY, proxy);
++ if(result)
++ goto init_failed;
++
++ res_easy_setopt(curl, CURLOPT_PROXYUSERPWD, userpwd);
++ if(result)
++ goto init_failed;
++
++ res_easy_setopt(curl, CURLOPT_PROXYAUTH, CURLAUTH_DIGEST);
++ if(result)
++ goto init_failed;
++
++ res_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
++ if(result)
++ goto init_failed;
++#if 0
++ res_easy_setopt(curl, CURLOPT_HTTPPROXYTUNNEL, 1L);
++ if(result)
++ goto init_failed;
++#endif
++
++ res_easy_setopt(curl, CURLOPT_HEADER, 1L);
++ if(result)
++ goto init_failed;
++
++ return CURLE_OK; /* success */
++
++init_failed:
++ return result; /* failure */
++}
++
++static CURLcode run1588(CURL *curl, const char *url, const char *userpwd,
++ const char *proxy)
++{
++ CURLcode result = CURLE_OK;
++
++ result = init1588(curl, url, userpwd, proxy);
++ if(result)
++ return result;
++
++ return curl_easy_perform(curl);
++}
++
++static CURLcode test_lib1588(const char *URL)
++{
++ CURLcode result = CURLE_OK;
++ CURL *curl = NULL;
++ const char *proxyuserpws = libtest_arg4;
++ struct curl_slist *host = NULL;
++ struct curl_slist *host2 = NULL;
++ char proxy1_resolve[128];
++ char proxy2_resolve[128];
++ char proxy1_connect[128];
++ char proxy2_connect[128];
++
++ if(test_argc < 3)
++ return TEST_ERR_MAJOR_BAD;
++
++ curl_msnprintf(proxy1_resolve, sizeof(proxy1_resolve),
++ "firstproxy:%s:%s", libtest_arg3, libtest_arg2);
++ curl_msnprintf(proxy2_resolve, sizeof(proxy2_resolve),
++ "secondproxy:%s:%s", libtest_arg3, libtest_arg2);
++
++ /* we connect to the fake host name but the right port number */
++ curl_msnprintf(proxy1_connect, sizeof(proxy1_connect),
++ "firstproxy:%s", libtest_arg3);
++ curl_msnprintf(proxy2_connect, sizeof(proxy2_connect),
++ "secondproxy:%s", libtest_arg3);
++
++ res_global_init(CURL_GLOBAL_ALL);
++ if(result)
++ return result;
++
++ curl = curl_easy_init();
++ if(!curl) {
++ curl_mfprintf(stderr, "curl_easy_init() failed\n");
++ curl_global_cleanup();
++ return TEST_ERR_MAJOR_BAD;
++ }
++
++ host = curl_slist_append(NULL, proxy1_resolve);
++ if(!host)
++ goto test_cleanup;
++ host2 = curl_slist_append(host, proxy2_resolve);
++ if(!host2)
++ goto test_cleanup;
++ host = host2;
++
++ start_test_timing();
++
++ easy_setopt(curl, CURLOPT_RESOLVE, host);
++
++ result = run1588(curl, URL, proxyuserpws, proxy1_connect);
++ if(result)
++ goto test_cleanup;
++
++ curl_mfprintf(stderr, "lib1588: now we do the request again\n");
++
++ result = run1588(curl, URL, proxyuserpws, proxy2_connect);
++
++test_cleanup:
++
++ /* proper cleanup sequence - type PB */
++
++ curl_easy_cleanup(curl);
++ curl_global_cleanup();
++ curl_slist_free_all(host);
++ return result;
++}
+--
+2.43.7
@@ -18,6 +18,7 @@ SRC_URI = " \
file://CVE-2026-5545.patch \
file://CVE-2026-6253.patch \
file://CVE-2026-6429.patch \
+ file://CVE-2026-7168.patch \
file://mbedtls.patch \
"