## gomarkdown/markdown IsSafeURL panics on short URLs

- 種別: advisory
- 重大度: high
- 関連技術: go, github
- CVE: CVE-2026-102941
- 公開日時: 2026-10-16T15:41:39.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-cv23-7vc5-jfh7)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-cv23-7vc5-jfh7

影響: go:github.com/gomarkdown/markdown < 0.0.0-20260724235538-61af6e1e6971 → 0.0.0-20260724235538-61af6e1e6971
Summary IsSafeURL slices url[:nPath] before checking that len(url) >= nPath, so a URL shorter than a path prefix (0, 1 or 2 bytes) triggers a slice-bounds panic, and this is reached end to end when the html.Safelink hardening flag is enabled and the input contains an empty or very short link destination, giving an unrecoverable crash DoS. Confirmed at HEAD (e08cff8; present since 2022). The defect parser/parser.go, IsSafeURL: go func IsSafeURL(url []byte) bool { nLink := len(url) for _, path :=…