{"cve":"CVE-2026-87859","nvd":{"published":"2026-09-11T10:16:53.253","modified":"2026-09-16T19:40:00.317","status":"Awaiting Analysis","description":"morgan is an HTTP request logger middleware for Node.js. In versions before 1.12.1, its escapeLogField() function does not escape the double quote character, which delimits the quoted fields of the Apache combined log format that morgan emits. An unauthenticated remote attacker who controls a value written to a quoted field, such as the User-Agent or Referer header, can include a double quote to close that field early, so a log consumer that parses the log by field position reads attacker-supplied text as the following field. In the built-in formats this makes the recorded value differ from the value that was sent, and in custom formats that quote an attacker-controlled token before a server-controlled one it can forge values such as the response status. No newline is injected, so record separation stays intact. The issue is fixed in morgan 1.12.1, which escapes the double quote. Users should upgrade to morgan 1.12.1 or later.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-117"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/expressjs/morgan/security/advisories/GHSA-9f6g-j8ch-79g4"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:52:53.108888569+00:00"},"epss":{"cve":"CVE-2026-87859","score":0.0041,"percentile":0.35287,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-9f6g-j8ch-79g4","url":"https://osv.dev/vulnerability/GHSA-9f6g-j8ch-79g4","summary":"morgan vulnerable to Log Injection via unescaped double quote in quoted log fields","modified":"2026-09-28T21:45:03.858040877Z","packages":[{"ecosystem":"npm","name":"morgan","purl":"pkg:npm/morgan","ranges":["<1.12.1"],"fixed":["1.12.1"]}]}],"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."]}