From 60345ecc4bcc2a7b1b9b497f8b6e1fa8cff7e935 Mon Sep 17 00:00:00 2001 From: Jiaying Song Date: Thu, 9 Apr 2026 14:16:32 +0800 Subject: [PATCH] python3-pyasn1: fix CVE-2026-23490 pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.2, a Denial-of-Service issue has been found that leads to memory exhaustion from malformed RELATIVE-OID with excessive continuation octets. This vulnerability is fixed in 0.6.2. References: https://nvd.nist.gov/vuln/detail/CVE-2026-23490 (From OE-Core rev: 205d360b49c7bbaa8709cb5a0b2e57457c32ad22) Signed-off-by: Jiaying Song Signed-off-by: Jinfeng Wang Signed-off-by: Yoann Congal Signed-off-by: Paul Barker --- .../recipes-devtools/python/python-pyasn1.inc | 3 +- .../python3-pyasn1/CVE-2026-23490.patch | 136 ++++++++++++++++++ 2 files changed, 138 insertions(+), 1 deletion(-) create mode 100644 meta/recipes-devtools/python/python3-pyasn1/CVE-2026-23490.patch diff --git a/meta/recipes-devtools/python/python-pyasn1.inc b/meta/recipes-devtools/python/python-pyasn1.inc index 530ff1c7c3..96b4a3b52a 100644 --- a/meta/recipes-devtools/python/python-pyasn1.inc +++ b/meta/recipes-devtools/python/python-pyasn1.inc @@ -18,7 +18,8 @@ inherit ptest SRC_URI += " \ file://run-ptest \ - " + file://CVE-2026-23490.patch \ +" RDEPENDS:${PN}-ptest += " \ python3-pytest \ diff --git a/meta/recipes-devtools/python/python3-pyasn1/CVE-2026-23490.patch b/meta/recipes-devtools/python/python3-pyasn1/CVE-2026-23490.patch new file mode 100644 index 0000000000..a79774003b --- /dev/null +++ b/meta/recipes-devtools/python/python3-pyasn1/CVE-2026-23490.patch @@ -0,0 +1,136 @@ +From d98d7bc91864e1e368d4849c26568e33c0dd0e27 Mon Sep 17 00:00:00 2001 +From: Simon Pichugin +Date: Wed, 28 Jan 2026 16:31:29 +0800 +Subject: [PATCH] Merge commit from fork + +Add limit of 20 continuation octets per OID arc to prevent a potential +memory exhaustion from excessive continuation bytes input. + +CVE: CVE-2026-23490 + +Upstream-Status: Backport [https://github.com/pyasn1/pyasn1/commit/3908f14422] + +Signed-off-by: Jiaying Song +--- + pyasn1/codec/ber/decoder.py | 13 ++++++- + tests/codec/ber/test_decoder.py | 65 +++++++++++++++++++++++++++++++++ + 2 files changed, 77 insertions(+), 1 deletion(-) + +diff --git a/pyasn1/codec/ber/decoder.py b/pyasn1/codec/ber/decoder.py +index 7cc863d..be8ba65 100644 +--- a/pyasn1/codec/ber/decoder.py ++++ b/pyasn1/codec/ber/decoder.py +@@ -35,6 +35,10 @@ noValue = base.noValue + + SubstrateUnderrunError = error.SubstrateUnderrunError + ++# Maximum number of continuation octets (high-bit set) allowed per OID arc. ++# 20 octets allows up to 140-bit integers, supporting UUID-based OIDs ++MAX_OID_ARC_CONTINUATION_OCTETS = 20 ++ + + class AbstractPayloadDecoder(object): + protoComponent = None +@@ -431,7 +435,14 @@ class ObjectIdentifierPayloadDecoder(AbstractSimplePayloadDecoder): + # Construct subid from a number of octets + nextSubId = subId + subId = 0 ++ continuationOctetCount = 0 + while nextSubId >= 128: ++ continuationOctetCount += 1 ++ if continuationOctetCount > MAX_OID_ARC_CONTINUATION_OCTETS: ++ raise error.PyAsn1Error( ++ 'OID arc exceeds maximum continuation octets limit (%d) ' ++ 'at position %d' % (MAX_OID_ARC_CONTINUATION_OCTETS, index) ++ ) + subId = (subId << 7) + (nextSubId & 0x7F) + if index >= substrateLen: + raise error.SubstrateUnderrunError( +@@ -1872,7 +1883,7 @@ class StreamingDecoder(object): + :py:class:`~pyasn1.error.SubstrateUnderrunError` object indicating + insufficient BER/CER/DER serialization on input to fully recover ASN.1 + objects from it. +- ++ + In the latter case the caller is advised to ensure some more data in + the input stream, then call the iterator again. The decoder will resume + the decoding process using the newly arrived data. +diff --git a/tests/codec/ber/test_decoder.py b/tests/codec/ber/test_decoder.py +index 3b97ce4..f033dfd 100644 +--- a/tests/codec/ber/test_decoder.py ++++ b/tests/codec/ber/test_decoder.py +@@ -450,6 +450,71 @@ class ObjectIdentifierDecoderTestCase(BaseTestCase): + ints2octs((0x06, 0x13, 0x88, 0x37, 0x83, 0xC6, 0xDF, 0xD4, 0xCC, 0xB3, 0xFF, 0xFF, 0xFE, 0xF0, 0xB8, 0xD6, 0xB8, 0xCB, 0xE2, 0xB6, 0x47)) + ) == ((2, 999, 18446744073709551535184467440737095), null) + ++ def testExcessiveContinuationOctets(self): ++ """Test that OID arcs with excessive continuation octets are rejected.""" ++ # Create a payload with 25 continuation octets (exceeds 20 limit) ++ # 0x81 bytes are continuation octets, 0x01 terminates ++ malicious_payload = bytes([0x06, 26]) + bytes([0x81] * 25) + bytes([0x01]) ++ try: ++ decoder.decode(malicious_payload) ++ except error.PyAsn1Error: ++ pass ++ else: ++ assert 0, 'Excessive continuation octets tolerated' ++ ++ def testMaxAllowedContinuationOctets(self): ++ """Test that OID arcs at the maximum continuation octets limit work.""" ++ # Create a payload with exactly 20 continuation octets (at limit) ++ # This should succeed ++ payload = bytes([0x06, 21]) + bytes([0x81] * 20) + bytes([0x01]) ++ try: ++ decoder.decode(payload) ++ except error.PyAsn1Error: ++ assert 0, 'Valid OID with 20 continuation octets rejected' ++ ++ def testOneOverContinuationLimit(self): ++ """Test boundary: 21 continuation octets (one over limit) is rejected.""" ++ payload = bytes([0x06, 22]) + bytes([0x81] * 21) + bytes([0x01]) ++ try: ++ decoder.decode(payload) ++ except error.PyAsn1Error: ++ pass ++ else: ++ assert 0, '21 continuation octets tolerated (should be rejected)' ++ ++ def testExcessiveContinuationInSecondArc(self): ++ """Test that limit applies to subsequent arcs, not just the first.""" ++ # First arc: valid simple byte (0x55 = 85, decodes to arc 2.5) ++ # Second arc: excessive continuation octets ++ payload = bytes([0x06, 27]) + bytes([0x55]) + bytes([0x81] * 25) + bytes([0x01]) ++ try: ++ decoder.decode(payload) ++ except error.PyAsn1Error: ++ pass ++ else: ++ assert 0, 'Excessive continuation in second arc tolerated' ++ ++ def testMultipleArcsAtLimit(self): ++ """Test multiple arcs each at the continuation limit work correctly.""" ++ # Two arcs, each with 20 continuation octets (both at limit) ++ arc1 = bytes([0x81] * 20) + bytes([0x01]) # 21 bytes ++ arc2 = bytes([0x81] * 20) + bytes([0x01]) # 21 bytes ++ payload = bytes([0x06, 42]) + arc1 + arc2 ++ try: ++ decoder.decode(payload) ++ except error.PyAsn1Error: ++ assert 0, 'Multiple valid arcs at limit rejected' ++ ++ def testExcessiveContinuationWithMaxBytes(self): ++ """Test with 0xFF continuation bytes (maximum value, not just 0x81).""" ++ # 0xFF bytes are also continuation octets (high bit set) ++ malicious_payload = bytes([0x06, 26]) + bytes([0xFF] * 25) + bytes([0x01]) ++ try: ++ decoder.decode(malicious_payload) ++ except error.PyAsn1Error: ++ pass ++ else: ++ assert 0, 'Excessive 0xFF continuation octets tolerated' + + class RealDecoderTestCase(BaseTestCase): + def testChar(self): +-- +2.34.1 +