CVE-2026-88015: rclone local: crafted Range request against a translated symlink panics (DoS)

When backend/local is used with --links/-l (or the links=true config option), each symlink is exposed as an rclone object whose content is the target path string, suffixed .rclonelink. Object.Open() decodes an incoming fs.RangeOption via Decode(o.Size()), then for a translated-symlink object passes the decoded offset straight into openTranslatedLink, which indexes the target string directly: linkdst[offset:].

RangeOption.Decode’s Start >= 0 branch (an ordinary Range: bytes=X- request) sets offset = o.Start with no upper bound, unlike its suffix-range branch (Start < 0, e.g. bytes=-N), which already clamps a too-large value to 0 - the fix for a prior, related crash (issue #6310: “bytes=-90407” against a 5-byte object panicked with “slice bounds out of range”, now covered by an existing regression test). The Start >= 0 branch never received the analogous protection.

A Range: bytes=<hugeStart>- request sent to rclone serve http/webdav (or any consumer of lib/http/serve’s Object(), which parses and decodes the client’s own Range header) against a directory containing a symlink therefore reaches linkdst[offset:] with offset far beyond the target string’s length, and Go panics with “slice bounds out of range” instead of returning an empty read.