{"id":"CVE-2024-1455","aliases":["GHSA-q84m-rmw3-4382","PYSEC-2026-1519"],"url":"https://o3.security/vulnerability/CVE-2024-1455","summary":"Billion Laughs Attack leading to DoS in langchain-ai/langchain","details":"The XMLOutputParser in LangChain uses the etree module from the XML parser in the standard python library which has some XML vulnerabilities; see: https://docs.python.org/3/library/xml.html\n\nThis primarily affects users that combine an LLM (or agent) with the `XMLOutputParser` and expose the component via an endpoint on a web-service. \n\nThis would allow a malicious party to attempt to manipulate the LLM to produce a malicious payload for the parser that would compromise the availability of the service.\n\nA successful attack is predicated on:\n\n1. Usage of XMLOutputParser\n2. Passing of malicious input into the XMLOutputParser either directly or by trying to manipulate an LLM to do so on the users behalf\n3. Exposing the component via a web-service","published":"2024-03-26T14:03:46.647Z","modified":"2026-08-12T03:51:20.726379666Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"langchain-core","fixedVersion":"0.1.35"}],"fix":{"url":"https://github.com/langchain-ai/langchain/commit/727d5023ce88e18e3074ef620a98137d26ff92a3","label":"langchain-ai/langchain@727d502"},"references":[{"type":"WEB","url":"https://huntr.com/bounties/4353571f-c70d-4bfd-ac08-3a89cecb45b6"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/1xxx/CVE-2024-1455.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-1455"},{"type":"FIX","url":"https://github.com/langchain-ai/langchain/commit/727d5023ce88e18e3074ef620a98137d26ff92a3"},{"type":"WEB","url":"https://github.com/langchain-ai/langchain/pull/17250"},{"type":"WEB","url":"https://github.com/langchain-ai/langchain/pull/19653"},{"type":"WEB","url":"https://github.com/langchain-ai/langchain/pull/19660"},{"type":"PACKAGE","url":"https://github.com/langchain-ai/langchain"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:20.726379666Z"}}