diff --git a/meta-python/recipes-devtools/python/python3-ecdsa/CVE-2026-33936.patch b/meta-python/recipes-devtools/python/python3-ecdsa/CVE-2026-33936.patch new file mode 100644 index 0000000000..f2d3743825 --- /dev/null +++ b/meta-python/recipes-devtools/python/python3-ecdsa/CVE-2026-33936.patch @@ -0,0 +1,56 @@ +From 41e6b7be293284ef8b1f102587f0da6eae1b753f Mon Sep 17 00:00:00 2001 +From: 0xmrma +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 +--- + 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) diff --git a/meta-python/recipes-devtools/python/python3-ecdsa_0.19.0.bb b/meta-python/recipes-devtools/python/python3-ecdsa_0.19.0.bb index 8e967f9259..0ae93fe3d9 100644 --- a/meta-python/recipes-devtools/python/python3-ecdsa_0.19.0.bb +++ b/meta-python/recipes-devtools/python/python3-ecdsa_0.19.0.bb @@ -10,6 +10,7 @@ inherit pypi setuptools3 python3native ptest SRC_URI += " \ file://run-ptest \ + file://CVE-2026-33936.patch \ " RDEPENDS:${PN}-ptest += " \