Bug 2494381

Summary: CVE-2026-27145 golang-github-openprinting-ipp-usb: golang crypto/x509: Denial of Service via excessive processing of DNS SAN entries [fedora-all]
Product: [Fedora] Fedora Reporter: jkelly <jkelly>
Component: golang-github-openprinting-ipp-usbAssignee: Zdenek Dohnal <zdohnal>
Status: ON_QA --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: 43CC: go-sig, zdohnal
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["1765a0c8-adb1-4223-88bf-d35a230e256a"]}
Fixed In Version: Doc Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2484207    

Description jkelly 2026-06-29 14:29:09 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 2026-06-30 07:25:19 UTC 
FEDORA-2026-d7dfd8e9ba (golang-github-openprinting-ipp-usb-0.9.34-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-d7dfd8e9ba
Comment 2 Fedora Update System 2026-07-01 01:40:07 UTC 
FEDORA-2026-d7dfd8e9ba 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-d7dfd8e9ba`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-d7dfd8e9ba

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