x/vulndb: Go vuln in golang.org/x: CVE-2026-42500

[thatnealpatel]

Placeholder issue for https://go.dev/issue/79576

[gopherbot]

Change https://go.dev/cl/781780 mentions this issue: data/reports: add 2 first-party reports

[gopherbot]

Change https://go.dev/cl/784921 mentions this issue: data/reports: add one x/image report