{"answers":{"affected":"4 open source packages ship an affected version, including fast-xml-parser. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-26278 in the wild and no public exploit code.","fix":"Upgrade fast-xml-parser to a fixed version for your release line: 4.5.4 or 5.3.6.","what":"CVE-2026-26278 is a high-severity denial of service vulnerability in NaturalIntelligence fast-xml-parser, published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-26278 and fix it if it is affected.\n\nWhat it is: CVE-2026-26278 is a high-severity denial of service vulnerability in NaturalIntelligence fast-xml-parser, published on 19 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-26278 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- fast-xml-parser (npm): affected from 4.1.3; fixed in 4.5.4\n- fast-xml-parser (npm): affected from 4.1.3; fixed in 4.5.4\n- fast-xml-parser (npm): affected from 5.0.0; fixed in 5.3.6\n- fast-xml-parser (npm): affected from 5.0.0; fixed in 5.3.6\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-26278/ (Markdown: https://insights.sbomify.com/CVE-2026-26278/index.md)","id":"CVE-2026-26278","markdown":"https://insights.sbomify.com/CVE-2026-26278/index.md","name":"CVE-2026-26278","record":{"aliases":["CLEANSTART-2026-DE27040","CLEANSTART-2026-FQ78730","DEBIAN-CVE-2026-26278","ECHO-058b-a6ce-5049","GHSA-jmr7-xgp7-cmfj","MINI-474x-5c6m-9w4f","MINI-5q6f-qwp7-jj42","MINI-694q-5cxw-h794","MINI-6c6f-4vqf-pjx5","MINI-7gh2-64q4-vfr9","MINI-7w7p-pjjr-jvq8","MINI-85pm-888r-mvcw","MINI-gqpr-mm95-95c3","MINI-gx9x-vrcj-cp6r","MINI-mr55-5j4f-3x2p","MINI-v59w-g7w6-28cg","MINI-vv2w-87cp-6vgj","MINI-x3gc-7w7m-rqqg","MINI-x8cq-4wjc-h6r8","ROOT-APP-NPM-CVE-2026-26278","UBUNTU-CVE-2026-26278"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"JavaScript XML parser","requires_auth":"none","summary":"An attacker can cause denial of service in applications using fast-xml-parser by submitting XML with unlimited entity expansion, freezing the application.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"fast-xml-parser","vendor":"naturalintelligence"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-776","name":"Improper Restriction of Recursive Entity References in DTDs"}],"description":"fast-xml-parser allows users to validate XML, parse XML to JS object, or build XML from JS object without C/C++ based libraries and no callback. In versions 4.1.3 through 5.3.5, the XML parser can be forced to do an unlimited amount of entity expansion. With a very small XML input, it’s possible to make the parser spend seconds or even minutes processing a single request, effectively freezing the application. Version 5.3.6 fixes the issue. As a workaround, avoid using DOCTYPE parsing by `processEntities: false` option.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"fast-xml-parser affected by DoS through entity expansion in DOCTYPE (no expansion limit)","id":"CVE-2026-26278","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":4,"n_references":3,"next":{"headline":"Froxlor Admin-to-Root Privilege Escalation via Input Validation Bypass + OS Command Injection","id":"CVE-2026-26279"},"packages":[{"ecosystem":"npm","fixed":["4.5.4"],"introduced":["4.1.3"],"last_affected":[],"package":"fast-xml-parser","purl":null,"source":"GHSA-jmr7-xgp7-cmfj"},{"ecosystem":"npm","fixed":["4.5.4"],"introduced":["4.1.3"],"last_affected":[],"package":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","source":"GHSA-jmr7-xgp7-cmfj"},{"ecosystem":"npm","fixed":["5.3.6"],"introduced":["5.0.0"],"last_affected":[],"package":"fast-xml-parser","purl":null,"source":"GHSA-jmr7-xgp7-cmfj"},{"ecosystem":"npm","fixed":["5.3.6"],"introduced":["5.0.0"],"last_affected":[],"package":"fast-xml-parser","purl":"pkg:npm/fast-xml-parser","source":"GHSA-jmr7-xgp7-cmfj"}],"prev":{"headline":"Gogs: DOM-based XSS via milestone selection","id":"CVE-2026-26276"},"products":["fast-xml-parser"],"published":"2026-02-19","related":[{"cvss_score":9.3,"headline":"fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names","id":"CVE-2026-25896","kev_date_added":null,"published":"2026-02-20"},{"cvss_score":7.5,"headline":"fast-xml-parser affected by numeric entity expansion bypassing all entity expansion limits (incomplete fix for CVE-2026-26278)","id":"CVE-2026-33036","kev_date_added":null,"published":"2026-03-20"},{"cvss_score":7.5,"headline":"fast-xml-parser has RangeError DoS Numeric Entities Bug","id":"CVE-2026-25128","kev_date_added":null,"published":"2026-01-30"},{"cvss_score":7.5,"headline":"ReDOS at currency parsing fast-xml-parser","id":"CVE-2024-41818","kev_date_added":null,"published":"2024-07-29"},{"cvss_score":7.5,"headline":"Regex Injection via Doctype Entities","id":"CVE-2023-34104","kev_date_added":null,"published":"2023-06-06"},{"cvss_score":6.1,"headline":"fast-xml-parser XMLBuilder: XML Comment and CDATA Injection via Unescaped Delimiters","id":"CVE-2026-41650","kev_date_added":null,"published":"2026-05-07"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-10","vendors":["NaturalIntelligence"]},"summary":"An attacker can cause denial of service in applications using fast-xml-parser by submitting XML with unlimited entity expansion, freezing the application.","url":"https://insights.sbomify.com/CVE-2026-26278/"}