CVE-2026-56860: Go Standard Library Net/url

Medium severity, CVSS 5.9. EPSS: 0.6% chance of exploitation in the next 30 days.

Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.

Affected products

• Go Standard Library Net/url: before 1.25.13 (fixed in 1.25.13); from 1.26.0-0, before 1.26.6 (fixed in 1.26.6); from 1.27.0-0, before 1.27.0-rc.3 (fixed in 1.27.0-rc.3)

Published 2026-08-13. Last modified 2026-09-03.