{"cve":"CVE-2026-42874","nvd":{"published":"2026-05-11T20:25:43.973","modified":"2026-10-26T18:10:00.173","status":"Deferred","description":"Microdot is a minimalistic Python web framework. Prior to 2.6.1, the Response.set_cookie() method does not sanitize its string arguments, and in particular will not detect the presence of the \\r\\n sequence in them. This can be a potential source of header injection attacks. For a header injection attack through this issue to be possible, an attacker must first infiltrate the client (for example through an independent XSS attack), so that it can send malicious information that is destined to be stored in a cookie by the server on behalf of the victim. An attacker that infiltrates one client can only orchestrate a header injection attack for that client, all other clients that were not infiltrated are safe. This vulnerability is fixed in 2.6.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N","score":3.7},"cwes":["CWE-113"],"references":["https://github.com/miguelgrinberg/microdot/blob/main/CHANGES.md","https://github.com/miguelgrinberg/microdot/commit/99b281b45faef8472410f2d56bfef496dfbd95d5","https://github.com/miguelgrinberg/microdot/security/advisories/GHSA-7wc8-wvc4-m498"],"products":[],"source":"nvd","synced_at":"2026-10-26T18:27:13.530666824+00:00"},"epss":{"cve":"CVE-2026-42874","score":0.00215,"percentile":0.11842,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-7wc8-wvc4-m498","url":"https://osv.dev/vulnerability/GHSA-7wc8-wvc4-m498","summary":"Microdot has HTTP response splitting in Response.set_cookie()","modified":"2026-07-13T16:43:25.193457064Z","packages":[{"ecosystem":"PyPI","name":"microdot","purl":"pkg:pypi/microdot","ranges":["<2.6.1"],"fixed":["2.6.1"]}]},{"id":"PYSEC-2026-2646","url":"https://osv.dev/vulnerability/PYSEC-2026-2646","summary":"Microdot has HTTP response splitting in Response.set_cookie()","modified":"2026-07-13T16:31:50.940234729Z","packages":[{"ecosystem":"PyPI","name":"microdot","purl":"pkg:pypi/microdot","ranges":["<2.6.1"],"fixed":["2.6.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}