Security Vulnerabilities
NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using built-in open() instead of nltk.pathsec.open(), allowing symlinks to escape trusted roots. Attackers who stage symlinked corpus files under a trusted data root can disclose outside-root content through normal corpus reader methods like channels(), domains(), and synonyms().
CVSS Score
8.2
EPSS Score
0.003
Published
2026-08-25
Nokogiri versions before 1.19.3 contain regular expression denial of service vulnerabilities in the CSS selector tokenizer affecting string-literal and identifier tokenization. Attackers can inject adversarial CSS selectors into methods like Node#css, Node#at_css, and Searchable#search to cause exponential regex backtracking and denial of service.
CVSS Score
8.7
EPSS Score
0.003
Published
2026-08-25
Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform parameters, causing heap allocations to leak and enabling denial of service against long-running processes.
CVSS Score
6.9
EPSS Score
0.003
Published
2026-08-25
Nokogiri versions before 1.19.1 fail to check the return value from xmlC14NExecute in the canonicalize method, returning an empty string on failure instead of raising an exception. Attackers can exploit this to bypass signature validation in downstream SAML libraries by providing invalid canonicalized XML that is incorrectly accepted as valid.
CVSS Score
6.9
EPSS Score
0.002
Published
2026-08-25
NLTK versions before 3.10.3 contain a path sandbox bypass vulnerability in corpus-reader constructors that allows attackers to read files outside the intended data root. Attackers can supply arbitrary corpus root paths to LinThesaurusCorpusReader and PanLexLiteCorpusReader constructors to access filesystem content and SQLite databases outside the pathsec sandbox boundary.
CVSS Score
8.8
EPSS Score
0.002
Published
2026-08-25
Nokogiri before 1.13.9 (CRuby implementation using packaged libraries) bundles libxml2 v2.9.14, which is affected by CVE-2022-40304 (data corruption / double-free from an entity reference cycle when entity content is allocated from a dict) and CVE-2022-40303 (integer overflows when parsing with XML_PARSE_HUGE). Nokogiri 1.13.9 upgrades the packaged libxml2 to v2.10.3 to address these issues. Processing crafted XML input may lead to denial of service or memory corruption. (The advisory also references CVE-2022-2309, a NULL pointer dereference via iterwalk/canonicalize, which maintainers determined does not affect Nokogiri users.)
CVSS Score
8.7
EPSS Score
0.004
Published
2026-08-25
Nokogiri versions before 1.13.5 contain an integer overflow vulnerability in packaged libxml2 buffer handling functions that allows attackers to cause out-of-bounds memory writes. Attackers can exploit this by crafting multi-gigabyte XML files to trigger buffer overflows resulting in information disclosure, data modification, or denial of service.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-08-25
Nokogiri before 1.13.2 (CRuby, when using packaged libraries) ships vendored libxml2 2.9.12 and libxslt 1.1.34, which are affected by two upstream CVEs. Via CVE-2021-30560 in libxslt, an application transforming XML with untrusted XSL stylesheets is vulnerable to a denial-of-service attack. Via CVE-2022-23308 in libxml2, an application parsing an untrusted document with parse option DTDVALID set to true and NOENT set to false may be vulnerable to denial of service, memory disclosure, or code execution. Nokogiri 1.13.2 upgrades vendored libxml2 to 2.9.13 and libxslt to 1.1.35.
CVSS Score
9.3
EPSS Score
0.004
Published
2026-08-25
Nokogiri before 1.14.3 (CRuby implementation only, when using the packaged libxml2) bundles libxml2 v2.10.3, which is vulnerable to NULL pointer dereferences in XML Schema processing (xmlSchemaFixupComplexType, CVE-2023-28484, and xmlSchemaCheckCOSSTDerivedOK). An attacker who supplies a crafted/malformed XML schema can cause libxml2 to dereference a NULL pointer and potentially segfault, resulting in a denial of service. Nokogiri 1.14.3 upgrades the packaged libxml2 to v2.10.4 to resolve these issues.
CVSS Score
8.7
EPSS Score
0.004
Published
2026-08-25
Nokogiri before 1.11.4 (CRuby implementation only, when the packaged/vendored libxml2 is used) bundles libxml2 2.9.10, which is affected by multiple vulnerabilities addressed in libxml2 2.9.12, including a memory leak in xmlSchemaValidateStream (CVE-2019-20388), a global buffer over-read in xmlEncodeEntitiesInternal (CVE-2020-24977), a heap-based buffer overflow (CVE-2021-3517), and an out-of-bounds read (CVE-2021-3518). Processing crafted XML documents may lead to denial of service, information disclosure, or memory corruption.
CVSS Score
8.7
EPSS Score
0.005
Published
2026-08-25