Bug 2494283

Summary: CVE-2026-27145 betterleaks: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries [fedora-all]
Product: [Fedora] Fedora Reporter: jkelly <jkelly>
Component: betterleaksAssignee: Mikel Olasagasti Uranga <mikel>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: go-sig, mikel
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["1765a0c8-adb1-4223-88bf-d35a230e256a"]}
Fixed In Version: betterleaks-1.6.0-1.el10_3 betterleaks-1.6.0-1.el9 betterleaks-1.6.0-1.el10_2 betterleaks-1.6.0-1.fc44 betterleaks-1.6.0-1.fc43 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-07-08 00:26:10 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2484207    

Description jkelly 2026-06-29 14:19:16 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

Comment 1 Fedora Update System 2026-06-29 18:49:30 UTC
FEDORA-EPEL-2026-1719298063 (betterleaks-1.6.0-1.el9) has been submitted as an update to Fedora EPEL 9.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-1719298063

Comment 2 Fedora Update System 2026-06-29 18:49:30 UTC
FEDORA-EPEL-2026-6e8fb57b18 (betterleaks-1.6.0-1.el10_3) has been submitted as an update to Fedora EPEL 10.3.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-6e8fb57b18

Comment 3 Fedora Update System 2026-06-29 18:49:31 UTC
FEDORA-EPEL-2026-85e4f2d067 (betterleaks-1.6.0-1.el10_2) has been submitted as an update to Fedora EPEL 10.2.
https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-85e4f2d067

Comment 4 Fedora Update System 2026-06-29 18:51:14 UTC
FEDORA-2026-97d351d54e (betterleaks-1.6.0-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-97d351d54e

Comment 5 Fedora Update System 2026-06-29 18:51:15 UTC
FEDORA-2026-6f573784e6 (betterleaks-1.6.0-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-6f573784e6

Comment 6 Fedora Update System 2026-06-30 00:23:27 UTC
FEDORA-EPEL-2026-6e8fb57b18 has been pushed to the Fedora EPEL 10.3 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-6e8fb57b18

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 7 Fedora Update System 2026-06-30 00:48:48 UTC
FEDORA-2026-6f573784e6 has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-6f573784e6`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-6f573784e6

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 8 Fedora Update System 2026-06-30 00:55:10 UTC
FEDORA-EPEL-2026-1719298063 has been pushed to the Fedora EPEL 9 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-1719298063

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 9 Fedora Update System 2026-06-30 01:01:07 UTC
FEDORA-EPEL-2026-85e4f2d067 has been pushed to the Fedora EPEL 10.2 testing repository.

You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2026-85e4f2d067

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 10 Fedora Update System 2026-06-30 01:25:15 UTC
FEDORA-2026-97d351d54e has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-97d351d54e`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-97d351d54e

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 11 Fedora Update System 2026-07-08 00:26:10 UTC
FEDORA-EPEL-2026-6e8fb57b18 (betterleaks-1.6.0-1.el10_3) has been pushed to the Fedora EPEL 10.3 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 12 Fedora Update System 2026-07-08 00:40:05 UTC
FEDORA-EPEL-2026-1719298063 (betterleaks-1.6.0-1.el9) has been pushed to the Fedora EPEL 9 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 13 Fedora Update System 2026-07-08 00:49:34 UTC
FEDORA-EPEL-2026-85e4f2d067 (betterleaks-1.6.0-1.el10_2) has been pushed to the Fedora EPEL 10.2 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 14 Fedora Update System 2026-07-08 00:57:33 UTC
FEDORA-2026-6f573784e6 (betterleaks-1.6.0-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 15 Fedora Update System 2026-07-08 01:10:40 UTC
FEDORA-2026-97d351d54e (betterleaks-1.6.0-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.