new file mode 100644
@@ -0,0 +1,56 @@
+From 41e6b7be293284ef8b1f102587f0da6eae1b753f Mon Sep 17 00:00:00 2001
+From: 0xmrma <moabdelaal442004@gmail.com>
+Date: Sun, 1 Mar 2026 09:18:21 +0200
+Subject: [PATCH] der: reject truncated lengths in octet/implicit/constructed
+
+CVE: CVE-2026-33936
+Upstream-Status: Backport [https://github.com/tlsfuzzer/python-ecdsa/commit/bd66899550d7185939bf27b75713a2ac9325a9d3]
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ src/ecdsa/der.py | 4 ++++
+ src/ecdsa/test_der.py | 13 +++++++++++++
+ 2 files changed, 17 insertions(+)
+
+diff --git a/src/ecdsa/der.py b/src/ecdsa/der.py
+index b291485..5bbfaa3 100644
+--- a/src/ecdsa/der.py
++++ b/src/ecdsa/der.py
+@@ -137,6 +137,8 @@ def remove_constructed(string):
+ )
+ tag = s0 & 0x1F
+ length, llen = read_length(string[1:])
++ if length > len(string) - 1 - llen:
++ raise UnexpectedDER("Length longer than the provided buffer")
+ body = string[1 + llen : 1 + llen + length]
+ rest = string[1 + llen + length :]
+ return tag, body, rest
+@@ -160,6 +162,8 @@ def remove_octet_string(string):
+ n = str_idx_as_int(string, 0)
+ raise UnexpectedDER("wanted type 'octetstring' (0x04), got 0x%02x" % n)
+ length, llen = read_length(string[1:])
++ if length > len(string) - 1 - llen:
++ raise UnexpectedDER("Length longer than the provided buffer")
+ body = string[1 + llen : 1 + llen + length]
+ rest = string[1 + llen + length :]
+ return body, rest
+diff --git a/src/ecdsa/test_der.py b/src/ecdsa/test_der.py
+index 0c2dc4d..28d231e 100644
+--- a/src/ecdsa/test_der.py
++++ b/src/ecdsa/test_der.py
+@@ -476,3 +476,16 @@ def test_oids(ids):
+ decoded_oid, rest = remove_object(encoded_oid)
+ assert rest == b""
+ assert decoded_oid == ids
++
++def test_remove_octet_string_rejects_truncated_length():
++ # OCTET STRING: declared length 4096, but only 3 bytes present
++ bad = b"\x04\x82\x10\x00" + b"ABC"
++ with pytest.raises(UnexpectedDER, match="Length longer than the provided buffer"):
++ remove_octet_string(bad)
++
++def test_remove_constructed_rejects_truncated_length():
++ # Constructed tag: 0xA0 (context-specific constructed, tag=0)
++ # declared length 4096, but only 3 bytes present
++ bad = b"\xA0\x82\x10\x00" + b"ABC"
++ with pytest.raises(UnexpectedDER, match="Length longer than the provided buffer"):
++ remove_constructed(bad)
@@ -10,6 +10,7 @@ inherit pypi setuptools3 python3native ptest
SRC_URI += " \
file://run-ptest \
+ file://CVE-2026-33936.patch \
"
RDEPENDS:${PN}-ptest += " \