CVE-2026-56860Network attack vector

Service interruption via quadratic relative-path resolution

Published Aug 13, 2026 · Updated Aug 13, 2026

Algorithmic complexity in Go standard library net/url allows remote attackers to interrupt services through crafted relative paths. The resolvePath helper repeatedly converts strings and rewrites buffers for each '..' segment, causing CPU time and allocations to grow quadratically. Exposure requires URL.Parse or URL.ResolveReference to process attacker-controlled relative paths with many parent segments; resource exhaustion can make the consuming service unavailable without reported data disclosure or modification.

CVSS severity5.9
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic complexity in Go standard library net/url allows remote attackers to interrupt services through crafted relative paths. The resolvePath helper repeatedly converts strings and rewrites buffers for each '..' segment, causing CPU time and allocations to grow quadratically. Exposure requires URL.Parse or URL.ResolveReference to process attacker-controlled relative paths with many parent segments; resource exhaustion can make the consuming service unavailable without reported data disclosure or modification.

The record

CVE
CVE-2026-56860
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
Go standard library
Product
net/url
Classifications
CWE-407, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.25.13
  2. Affected versionversion=1.26.0-0 <1.26.6
  3. Affected versionversion=1.27.0-0 <1.27.0-rc.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Go standard library · net/urlversion=0 <1.25.13; version=1.26.0-0 <1.26.6; version=1.27.0-0 <1.27.0-rc.3

Published CVSS scores

5.9CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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