Vulnerability in Alexcorvi Anchorme
CVE-2026-103043
anchorme through 3.0.8 contains a regular expression denial of service vulnerability in the IPv6 host extraction regex due to catastrophic backtracking. Attackers can supply specially crafted input strings with repeated patterns to cause exponential regex engine backtracking, blocking the Node.js event loop and denying service to other requests.
Vulnerability class: ReDoS (Regular Expression Denial of Service)
Published .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- gist.github.com/mmadersbacher/46050b4224eb979431986cdef1dd2ad3 (third-party-advisory)
- github.com/alexcorvi/anchorme.js/blob/f3ae9850baa344f27b46bb149e9b891831d273b1/… (technical-description)
- www.npmjs.com/package/anchorme (product)
- github.com/alexcorvi/anchorme.js (product)
- www.vulncheck.com/advisories/anchorme-through-3.0.8-regular-expression-denial-o… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-103043?
- CVE-2026-103043 is a high-severity vulnerability in Alexcorvi Anchorme, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2026-09-29.
- How severe is CVE-2026-103043?
- High severity. CVSS v3 base score is 7.5 out of 10.