Description
Within HostnameError.Error(), when constructing an error string, there is no limit to the number of hosts that will be printed out. Furthermore, the error string is constructed by repeated string concatenation, leading to quadratic runtime. Therefore, a certificate provided by a malicious actor can result in excessive resource consumption.
References (4)
Core 4
Core References
Patch
https://go.dev/cl/725920
Issue Tracking, Patch
https://go.dev/issue/76445
Mailing List, Release Notes
https://groups.google.com/g/golang-announce/c/8FJoBkPddm4
Vendor Advisory
https://pkg.go.dev/vuln/GO-2025-4155
Scores
CVSS v3
7.5
EPSS
0.0045
EPSS Percentile
35.6%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-295
Status
published
Products (1)
golang/go
< 1.24.11
Published
Dec 02, 2025
Tracked Since
Feb 18, 2026