Bug 2480756 (CVE-2026-39821) - CVE-2026-39821 golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna: Privilege escalation via incorrect Punycode label processing
Summary: CVE-2026-39821 golang.org/x/net/idna: golang: net/http: golang.org/x/net/idna...
Keywords:
Status: NEW
Alias: CVE-2026-39821
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2487627
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-22 16:01 UTC by OSIDB Bzimport
Modified: 2026-07-17 00:47 UTC (History)
157 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:30853 0 None None None 2026-06-29 02:33:37 UTC
Red Hat Product Errata RHSA-2026:30854 0 None None None 2026-06-29 04:50:37 UTC
Red Hat Product Errata RHSA-2026:30855 0 None None None 2026-06-29 18:11:40 UTC
Red Hat Product Errata RHSA-2026:34357 0 None None None 2026-07-01 18:36:20 UTC
Red Hat Product Errata RHSA-2026:34359 0 None None None 2026-07-01 19:21:16 UTC
Red Hat Product Errata RHSA-2026:34789 0 None None None 2026-07-07 09:57:07 UTC
Red Hat Product Errata RHSA-2026:35826 0 None None None 2026-07-06 02:57:10 UTC
Red Hat Product Errata RHSA-2026:35827 0 None None None 2026-07-06 02:25:56 UTC
Red Hat Product Errata RHSA-2026:35828 0 None None None 2026-07-06 02:52:42 UTC
Red Hat Product Errata RHSA-2026:35829 0 None None None 2026-07-06 05:17:14 UTC
Red Hat Product Errata RHSA-2026:35830 0 None None None 2026-07-06 03:39:55 UTC
Red Hat Product Errata RHSA-2026:35831 0 None None None 2026-07-06 03:37:20 UTC
Red Hat Product Errata RHSA-2026:36796 0 None None None 2026-07-08 15:51:32 UTC
Red Hat Product Errata RHSA-2026:37435 0 None None None 2026-07-09 19:53:39 UTC
Red Hat Product Errata RHSA-2026:37436 0 None None None 2026-07-09 19:42:44 UTC
Red Hat Product Errata RHSA-2026:38995 0 None None None 2026-07-13 14:12:40 UTC
Red Hat Product Errata RHSA-2026:39005 0 None None None 2026-07-13 16:00:19 UTC
Red Hat Product Errata RHSA-2026:39573 0 None None None 2026-07-15 00:43:11 UTC
Red Hat Product Errata RHSA-2026:39879 0 None None None 2026-07-15 12:08:48 UTC
Red Hat Product Errata RHSA-2026:41019 0 None None None 2026-07-16 14:31:57 UTC

Description OSIDB Bzimport 2026-05-22 16:01:15 UTC 
The ToASCII and ToUnicode functions incorrectly accept Punycode-encoded labels that decode to an ASCII-only label. For example, ToUnicode("xn--example-.com") incorrectly returns the name "example.com" rather than an error. This behavior can lead to privilege escalation in programs using the idna package. For example, a program which performs privilege checks on the ASCII hostname may reject "example.com" but permit "xn--example-.com". If that program subsequently converts the ASCII hostname to Unicode, it will inadvertently permits access to the Unicode name "example.com".
Comment 1 errata-xmlrpc 2026-06-29 02:33:29 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:30853 https://access.redhat.com/errata/RHSA-2026:30853
Comment 2 errata-xmlrpc 2026-06-29 04:50:30 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:30854 https://access.redhat.com/errata/RHSA-2026:30854
Comment 3 errata-xmlrpc 2026-06-29 18:11:31 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:30855 https://access.redhat.com/errata/RHSA-2026:30855
Comment 4 errata-xmlrpc 2026-07-01 18:36:12 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:34357 https://access.redhat.com/errata/RHSA-2026:34357
Comment 5 errata-xmlrpc 2026-07-01 19:21:07 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:34359 https://access.redhat.com/errata/RHSA-2026:34359
Comment 6 errata-xmlrpc 2026-07-06 02:25:48 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:35827 https://access.redhat.com/errata/RHSA-2026:35827
Comment 7 errata-xmlrpc 2026-07-06 02:52:34 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:35828 https://access.redhat.com/errata/RHSA-2026:35828
Comment 8 errata-xmlrpc 2026-07-06 02:57:01 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:35826 https://access.redhat.com/errata/RHSA-2026:35826
Comment 9 errata-xmlrpc 2026-07-06 03:37:13 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:35831 https://access.redhat.com/errata/RHSA-2026:35831
Comment 10 errata-xmlrpc 2026-07-06 03:39:46 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:35830 https://access.redhat.com/errata/RHSA-2026:35830
Comment 11 errata-xmlrpc 2026-07-06 05:17:06 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:35829 https://access.redhat.com/errata/RHSA-2026:35829
Comment 14 errata-xmlrpc 2026-07-07 09:56:59 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.22

Via RHSA-2026:34789 https://access.redhat.com/errata/RHSA-2026:34789
Comment 15 errata-xmlrpc 2026-07-08 15:51:24 UTC 
This issue has been addressed in the following products:

  RHEM 1.0 for RHEL 9

Via RHSA-2026:36796 https://access.redhat.com/errata/RHSA-2026:36796
Comment 16 errata-xmlrpc 2026-07-09 19:42:36 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:37436 https://access.redhat.com/errata/RHSA-2026:37436
Comment 17 errata-xmlrpc 2026-07-09 19:53:32 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:37435 https://access.redhat.com/errata/RHSA-2026:37435
Comment 18 errata-xmlrpc 2026-07-13 14:12:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:38995 https://access.redhat.com/errata/RHSA-2026:38995
Comment 19 errata-xmlrpc 2026-07-13 16:00:10 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:39005 https://access.redhat.com/errata/RHSA-2026:39005
Comment 20 errata-xmlrpc 2026-07-15 00:43:03 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:39573 https://access.redhat.com/errata/RHSA-2026:39573
Comment 21 errata-xmlrpc 2026-07-15 12:08:41 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:39879 https://access.redhat.com/errata/RHSA-2026:39879
Comment 22 errata-xmlrpc 2026-07-16 14:31:50 UTC 
This issue has been addressed in the following products:

  RHEM 1.1 for RHEL 10
  RHEM 1.1 for RHEL 9

Via RHSA-2026:41019 https://access.redhat.com/errata/RHSA-2026:41019
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