Go standard library url up to 1.25.12/1.26.5 Path Resolution algorithmic complexity

Summaryinfo

A vulnerability was found in Go standard library url up to 1.25.12/1.26.5. It has been classified as problematic. This affects an unknown part of the component Path Resolution. Performing a manipulation results in algorithmic complexity. This vulnerability is cataloged as CVE-2026-56860. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Go standard library url up to 1.25.12/1.26.5. This affects an unknown code block of the component Path Resolution. The manipulation with an unknown input leads to a algorithmic complexity vulnerability. CWE is classifying the issue as CWE-407. An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached. This is going to have an impact on availability. The summary by CVE is:

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.

This vulnerability is uniquely identified as CVE-2026-56860 since 06/23/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 1.25.13, 1.26.6 or 1.27.0-rc.3 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

• Software Library

Vendor

• Go standard library

Name

• url

Version

• 1.25.0
• 1.25.1
• 1.25.2
• 1.25.3
• 1.25.4
• 1.25.5
• 1.25.6
• 1.25.7
• 1.25.8
• 1.25.9
• 1.25.10
• 1.25.11
• 1.25.12
• 1.26.0
• 1.26.1
• 1.26.2
• 1.26.3
• 1.26.4
• 1.26.5

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion