new file mode 100644
@@ -0,0 +1,295 @@
+From 54bce5dd1dce8839ea64e0bddebe4c6f8fd2cc6c Mon Sep 17 00:00:00 2001
+From: Eric Blankenhorn <eric@wolfssl.com>
+Date: Wed, 8 Apr 2026 16:27:07 -0500
+Subject: [PATCH] Fix partial chain verification
+
+(cherry picked from commit a6fd25b94e0c03c1be265a4454390d7225e81129)
+
+CVE: CVE-2026-6091
+Upstream-Status: Backport [https://github.com/wolfSSL/wolfssl/commit/a6fd25b94e0c03c1be265a4454390d7225e81129]
+
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ src/x509_str.c | 90 ++++++++++++++++++++++-
+ tests/api/test_ossl_x509_str.c | 127 +++++++++++++++++++++++++++++++++
+ 2 files changed, 216 insertions(+), 1 deletion(-)
+
+diff --git a/src/x509_str.c b/src/x509_str.c
+index 90113caed..01e975198 100644
+--- a/src/x509_str.c
++++ b/src/x509_str.c
+@@ -552,6 +552,53 @@ static int X509VerifyCertSetupRetry(WOLFSSL_X509_STORE_CTX* ctx,
+ return ret;
+ }
+
++/* Returns 1 if cur and x509 have identical DER encodings, 0 otherwise. */
++static int X509DerEquals(WOLFSSL_X509* cur, WOLFSSL_X509* x509)
++{
++ if (cur == NULL || cur->derCert == NULL ||
++ x509 == NULL || x509->derCert == NULL) {
++ return 0;
++ }
++ if (cur->derCert->length != x509->derCert->length)
++ return 0;
++ return XMEMCMP(cur->derCert->buffer, x509->derCert->buffer,
++ x509->derCert->length) == 0;
++}
++
++/* Returns 1 if x509's DER matches an entry in either origTrustedSk (an
++ * immutable snapshot of the caller's trusted set captured before any
++ * intermediates were injected for this verification call) or in
++ * store->trusted. Returns 0 otherwise. Used by the
++ * X509_V_FLAG_PARTIAL_CHAIN fallback to confirm that a chain actually
++ * terminates at a caller-trusted certificate. */
++static int X509StoreCertIsTrusted(WOLFSSL_X509_STORE* store,
++ WOLFSSL_X509* x509, WOLF_STACK_OF(WOLFSSL_X509)* origTrustedSk)
++{
++ int i;
++ int n;
++
++ if (x509 == NULL || x509->derCert == NULL)
++ return 0;
++
++ if (origTrustedSk != NULL) {
++ n = wolfSSL_sk_X509_num(origTrustedSk);
++ for (i = 0; i < n; i++) {
++ if (X509DerEquals(wolfSSL_sk_X509_value(origTrustedSk, i), x509))
++ return 1;
++ }
++ }
++
++ if (store != NULL && store->trusted != NULL) {
++ n = wolfSSL_sk_X509_num(store->trusted);
++ for (i = 0; i < n; i++) {
++ if (X509DerEquals(wolfSSL_sk_X509_value(store->trusted, i), x509))
++ return 1;
++ }
++ }
++
++ return 0;
++}
++
+ /* Verifies certificate chain using WOLFSSL_X509_STORE_CTX
+ * returns 1 on success or <= 0 on failure.
+ */
+@@ -570,6 +617,7 @@ int wolfSSL_X509_verify_cert(WOLFSSL_X509_STORE_CTX* ctx)
+ WOLF_STACK_OF(WOLFSSL_X509)* certs = NULL;
+ WOLF_STACK_OF(WOLFSSL_X509)* certsToUse = NULL;
+ WOLF_STACK_OF(WOLFSSL_X509)* failedCerts = NULL;
++ WOLF_STACK_OF(WOLFSSL_X509)* origTrustedSk = NULL;
+ WOLFSSL_ENTER("wolfSSL_X509_verify_cert");
+
+ if (ctx == NULL || ctx->store == NULL || ctx->store->cm == NULL
+@@ -586,9 +634,37 @@ int wolfSSL_X509_verify_cert(WOLFSSL_X509_STORE_CTX* ctx)
+ if (certs == NULL &&
+ wolfSSL_sk_X509_num(ctx->ctxIntermediates) > 0) {
+ certsToUse = wolfSSL_sk_X509_new_null();
++ if (certsToUse == NULL) {
++ ret = WOLFSSL_FAILURE;
++ goto exit;
++ }
+ ret = addAllButSelfSigned(certsToUse, ctx->ctxIntermediates, NULL);
++ /* certsToUse holds only injected intermediates, none are trusted, so
++ * leave origTrustedSk NULL (empty snapshot). */
++ certs = certsToUse;
+ }
+ else {
++ /* Snapshot the caller-trusted entries before injecting the
++ * caller-supplied untrusted intermediates. Only the entries already
++ * present count as trusted for the partial-chain check below, and
++ * we need a stable reference because X509VerifyCertSetupRetry may
++ * remove nodes from `certs` during chain building. */
++ if (certs != NULL && wolfSSL_sk_X509_num(certs) > 0) {
++ int j;
++ int n = wolfSSL_sk_X509_num(certs);
++ origTrustedSk = wolfSSL_sk_X509_new_null();
++ if (origTrustedSk == NULL) {
++ ret = WOLFSSL_FAILURE;
++ goto exit;
++ }
++ for (j = 0; j < n; j++) {
++ if (wolfSSL_sk_X509_push(origTrustedSk,
++ wolfSSL_sk_X509_value(certs, j)) <= 0) {
++ ret = WOLFSSL_FAILURE;
++ goto exit;
++ }
++ }
++ }
+ /* Add the intermediates provided on init to the list of untrusted
+ * intermediates to be used */
+ ret = addAllButSelfSigned(certs, ctx->ctxIntermediates, &numInterAdd);
+@@ -677,9 +753,17 @@ int wolfSSL_X509_verify_cert(WOLFSSL_X509_STORE_CTX* ctx)
+ * a trusted CA in the CM */
+ ret = X509StoreVerifyCert(ctx);
+ if (ret != WOLFSSL_SUCCESS) {
++ /* WOLFSSL_PARTIAL_CHAIN may only terminate the chain at a
++ * certificate the caller actually trusts. The previous
++ * "added == 1" guard merely confirmed that some untrusted
++ * intermediate had been temporarily loaded into the
++ * CertManager during chain building, which would accept
++ * chains that never reach a trust anchor. Verify that
++ * ctx->current_cert is itself in the original trust set. */
+ if (((ctx->flags & WOLFSSL_PARTIAL_CHAIN) ||
+ (ctx->store->param->flags & WOLFSSL_PARTIAL_CHAIN)) &&
+- (added == 1)) {
++ X509StoreCertIsTrusted(ctx->store, ctx->current_cert,
++ origTrustedSk)) {
+ wolfSSL_sk_X509_push(ctx->chain, ctx->current_cert);
+ ret = WOLFSSL_SUCCESS;
+ } else {
+@@ -749,6 +833,10 @@ exit:
+ if (certsToUse != NULL) {
+ wolfSSL_sk_X509_free(certsToUse);
+ }
++ if (origTrustedSk != NULL) {
++ /* Shallow free: only the snapshot's stack nodes, not the X509s. */
++ wolfSSL_sk_X509_free(origTrustedSk);
++ }
+
+ /* Enforce hostname / IP verification from X509_VERIFY_PARAM if set.
+ * Always check against the leaf (end-entity) certificate, captured in
+diff --git a/tests/api/test_ossl_x509_str.c b/tests/api/test_ossl_x509_str.c
+index 99b82877c..01ed9edfb 100644
+--- a/tests/api/test_ossl_x509_str.c
++++ b/tests/api/test_ossl_x509_str.c
+@@ -785,6 +785,127 @@ static int test_wolfSSL_X509_STORE_CTX_ex11(X509_STORE_test_data *testData)
+ return EXPECT_RESULT();
+ }
+
++static int test_wolfSSL_X509_STORE_CTX_ex_partial_chain_neg(
++ X509_STORE_test_data *testData)
++{
++ EXPECT_DECLS;
++ X509_STORE* store = NULL;
++ X509_STORE_CTX* ctx = NULL;
++ STACK_OF(X509)* untrusted = NULL;
++
++ /* Negative partial-chain test: with X509_V_FLAG_PARTIAL_CHAIN set, the
++ * intermediates are supplied ONLY as untrusted (passed through the
++ * X509_STORE_CTX_init "chain" argument and never added to the store).
++ * No certificate in the chain is in the store, so verification must
++ * fail. Pre-fix, wolfSSL_X509_verify_cert would incorrectly accept
++ * this chain because its partial-chain fallback only checked that some
++ * intermediate had been temporarily loaded into the CertManager, not
++ * that any chain certificate was actually trusted. */
++ ExpectNotNull(store = X509_STORE_new());
++ /* Intentionally do NOT add x509CaInt, x509CaInt2, or x509Ca. */
++ ExpectIntEQ(X509_STORE_set_flags(store, X509_V_FLAG_PARTIAL_CHAIN), 1);
++
++ ExpectNotNull(untrusted = sk_X509_new_null());
++ ExpectIntGT(sk_X509_push(untrusted, testData->x509CaInt2), 0);
++ ExpectIntGT(sk_X509_push(untrusted, testData->x509CaInt), 0);
++
++ ExpectNotNull(ctx = X509_STORE_CTX_new());
++ ExpectIntEQ(X509_STORE_CTX_init(ctx, store, testData->x509Leaf, untrusted),
++ 1);
++ /* Must NOT verify: partial-chain does not relax the trust requirement. */
++ ExpectIntNE(X509_verify_cert(ctx), 1);
++ /* Verify the failure is specifically due to missing trust anchor, not
++ * some unrelated error. */
++ ExpectIntEQ(X509_STORE_CTX_get_error(ctx),
++ X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY);
++
++ X509_STORE_CTX_free(ctx);
++ X509_STORE_free(store);
++ sk_X509_free(untrusted);
++ return EXPECT_RESULT();
++}
++
++static int test_wolfSSL_X509_STORE_CTX_ex_partial_chain_mixed(
++ X509_STORE_test_data *testData)
++{
++ EXPECT_DECLS;
++ X509_STORE* store = NULL;
++ X509_STORE_CTX* ctx = NULL;
++ STACK_OF(X509)* untrusted = NULL;
++
++ /* Mixed trusted-store + untrusted-chain partial-chain test: the store
++ * trusts an intermediate (x509CaInt2, the leaf's direct issuer), while
++ * an additional intermediate (x509CaInt) is supplied only as untrusted
++ * via the chain argument. With X509_V_FLAG_PARTIAL_CHAIN, verification
++ * must succeed by terminating at the trusted intermediate. This test
++ * exercises the snapshot-based trust check in X509StoreCertIsTrusted:
++ * the untrusted intermediate injected during verification must not be
++ * treated as a trust anchor, but the intermediate already in the store
++ * must be. */
++ ExpectNotNull(store = X509_STORE_new());
++ ExpectIntEQ(X509_STORE_add_cert(store, testData->x509CaInt2), 1);
++ ExpectIntEQ(X509_STORE_set_flags(store, X509_V_FLAG_PARTIAL_CHAIN), 1);
++
++ ExpectNotNull(untrusted = sk_X509_new_null());
++ ExpectIntGT(sk_X509_push(untrusted, testData->x509CaInt), 0);
++
++ ExpectNotNull(ctx = X509_STORE_CTX_new());
++ ExpectIntEQ(X509_STORE_CTX_init(ctx, store, testData->x509Leaf, untrusted),
++ 1);
++ /* Must verify: chain terminates at trusted intermediate in the store. */
++ ExpectIntEQ(X509_verify_cert(ctx), 1);
++
++ X509_STORE_CTX_free(ctx);
++ X509_STORE_free(store);
++ sk_X509_free(untrusted);
++ return EXPECT_RESULT();
++}
++
++static int test_wolfSSL_X509_STORE_CTX_ex_partial_chain_untrusted_terminal(
++ X509_STORE_test_data *testData)
++{
++ EXPECT_DECLS;
++ X509_STORE* store = NULL;
++ X509_STORE_CTX* ctx = NULL;
++ STACK_OF(X509)* untrusted = NULL;
++
++ /* Partial-chain boundary test: the store trusts a CA (x509Ca) that is
++ * NOT reachable from the leaf given the supplied untrusted intermediates,
++ * and an untrusted intermediate (x509CaInt2) IS the terminal of the
++ * (truncated) chain. With X509_V_FLAG_PARTIAL_CHAIN set, verification
++ * must FAIL because the chain terminates at an untrusted certificate.
++ *
++ * This test specifically targets the snapshot-based trust check in
++ * X509StoreCertIsTrusted. Before addAllButSelfSigned injects
++ * x509CaInt2, origTrustedSk is snapshotted from the caller-trusted set
++ * and contains only x509Ca. When the chain terminates at x509CaInt2,
++ * the trust check consults origTrustedSk (not the mutated working
++ * stack) and correctly finds no match. A regression that consulted
++ * the post-injection working stack instead of the snapshot would
++ * incorrectly mark x509CaInt2 as trusted and cause verification to
++ * succeed. */
++ ExpectNotNull(store = X509_STORE_new());
++ ExpectIntEQ(X509_STORE_add_cert(store, testData->x509Ca), 1);
++ ExpectIntEQ(X509_STORE_set_flags(store, X509_V_FLAG_PARTIAL_CHAIN), 1);
++
++ /* Only x509CaInt2 supplied as untrusted; x509CaInt is intentionally
++ * withheld so the chain cannot actually reach the trusted x509Ca. */
++ ExpectNotNull(untrusted = sk_X509_new_null());
++ ExpectIntGT(sk_X509_push(untrusted, testData->x509CaInt2), 0);
++
++ ExpectNotNull(ctx = X509_STORE_CTX_new());
++ ExpectIntEQ(X509_STORE_CTX_init(ctx, store, testData->x509Leaf, untrusted),
++ 1);
++ /* Must NOT verify: the chain terminal (x509CaInt2) is not in the
++ * original trust set, even though the store is non-empty. */
++ ExpectIntNE(X509_verify_cert(ctx), 1);
++
++ X509_STORE_CTX_free(ctx);
++ X509_STORE_free(store);
++ sk_X509_free(untrusted);
++ return EXPECT_RESULT();
++}
++
+ #ifdef HAVE_ECC
+ static int test_wolfSSL_X509_STORE_CTX_ex12(void)
+ {
+@@ -870,6 +991,12 @@ int test_wolfSSL_X509_STORE_CTX_ex(void)
+ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex9(&testData), 1);
+ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex10(&testData), 1);
+ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex11(&testData), 1);
++ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex_partial_chain_neg(&testData), 1);
++ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex_partial_chain_mixed(&testData),
++ 1);
++ ExpectIntEQ(
++ test_wolfSSL_X509_STORE_CTX_ex_partial_chain_untrusted_terminal(
++ &testData), 1);
+ #ifdef HAVE_ECC
+ ExpectIntEQ(test_wolfSSL_X509_STORE_CTX_ex12(), 1);
+ #endif
new file mode 100644
@@ -0,0 +1,30 @@
+From 62e57461f512849af4f466f77594085c90ffad73 Mon Sep 17 00:00:00 2001
+From: Eric Blankenhorn <eric@wolfssl.com>
+Date: Tue, 14 Apr 2026 07:58:43 -0500
+Subject: [PATCH] Fix from review
+
+(cherry picked from commit c873f3f77da8273e160612468f08892b2ba0ed99)
+
+CVE: CVE-2026-6091
+Upstream-Status: Backport [https://github.com/wolfSSL/wolfssl/commit/c873f3f77da8273e160612468f08892b2ba0ed99]
+
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ src/x509_str.c | 4 ++++
+ 1 file changed, 4 insertions(+)
+
+diff --git a/src/x509_str.c b/src/x509_str.c
+index 01e975198..67e3fcae6 100644
+--- a/src/x509_str.c
++++ b/src/x509_str.c
+@@ -765,6 +765,10 @@ int wolfSSL_X509_verify_cert(WOLFSSL_X509_STORE_CTX* ctx)
+ X509StoreCertIsTrusted(ctx->store, ctx->current_cert,
+ origTrustedSk)) {
+ wolfSSL_sk_X509_push(ctx->chain, ctx->current_cert);
++ /* Clear error set by the failed X509StoreVerifyCert
++ * attempt; the partial-chain fallback accepted the
++ * chain at a caller-trusted certificate. */
++ ctx->error = 0;
+ ret = WOLFSSL_SUCCESS;
+ } else {
+ X509VerifyCertSetupRetry(ctx, certs, failedCerts,
new file mode 100644
@@ -0,0 +1,36 @@
+From 13c4a12c9904a2e50d1729d8a6899f111f3bcd2a Mon Sep 17 00:00:00 2001
+From: Eric Blankenhorn <eric@wolfssl.com>
+Date: Tue, 14 Apr 2026 07:41:30 -0500
+Subject: [PATCH] Fix from review
+
+(cherry picked from commit 2b503dae543d09c63a08b1e24238e0e9ce1ac6c5)
+
+CVE: CVE-2026-6091
+Upstream-Status: Backport [https://github.com/wolfSSL/wolfssl/commit/2b503dae543d09c63a08b1e24238e0e9ce1ac6c5]
+
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ tests/api/test_ossl_x509_str.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/tests/api/test_ossl_x509_str.c b/tests/api/test_ossl_x509_str.c
+index 01ed9edfb..14f3538a4 100644
+--- a/tests/api/test_ossl_x509_str.c
++++ b/tests/api/test_ossl_x509_str.c
+@@ -854,6 +854,7 @@ static int test_wolfSSL_X509_STORE_CTX_ex_partial_chain_mixed(
+ 1);
+ /* Must verify: chain terminates at trusted intermediate in the store. */
+ ExpectIntEQ(X509_verify_cert(ctx), 1);
++ ExpectIntEQ(X509_STORE_CTX_get_error(ctx), X509_V_OK);
+
+ X509_STORE_CTX_free(ctx);
+ X509_STORE_free(store);
+@@ -899,6 +900,8 @@ static int test_wolfSSL_X509_STORE_CTX_ex_partial_chain_untrusted_terminal(
+ /* Must NOT verify: the chain terminal (x509CaInt2) is not in the
+ * original trust set, even though the store is non-empty. */
+ ExpectIntNE(X509_verify_cert(ctx), 1);
++ ExpectIntEQ(X509_STORE_CTX_get_error(ctx),
++ X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY);
+
+ X509_STORE_CTX_free(ctx);
+ X509_STORE_free(store);
@@ -19,6 +19,9 @@ SRC_URI = " \
file://CVE-2026-10098-2.patch \
file://CVE-2026-10512.patch \
file://CVE-2026-55958.patch \
+ file://CVE-2026-6091-1.patch \
+ file://CVE-2026-6091-2.patch \
+ file://CVE-2026-6091-3.patch \
"
SRCREV = "1d363f3adceba9d1478230ede476a37b0dcdef24"