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This CVE record has been updated after NVD enrichment efforts were completed. Enrichment data supplied by the NVD may require amendment due to these changes.
Description
NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.
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Title: Unbound de NLnet Labs, Description: NLnet Labs Unbound 1.14.0 hasta la versión 1.25.0 inclusive tiene una vulnerabilidad que resulta en un desbordamiento de montículo al codificar múltiples opciones NSID y/o DNS Cookie EDNS y/o EDNS Padding en el paquete de respuesta. Las opciones relevantes ('nsid', 'answer-cookie', 'pad-responses' (predeterminado)) deben estar habilitadas para que la vulnerabilidad sea explotada. Un adversario que puede consultar Unbound puede explotar la vulnerabilidad adjuntando múltiples opciones NSID y/o DNS Cookie EDNS y/o EDNS Padding a la consulta. Un fallo en el cálculo del tamaño del campo EDNS trunca el valor correcto, lo que permite al codificador desbordar el espacio disponible al escribir. Esos dos combinados conducen a una escritura de desbordamiento de montículo de datos controlados por Unbound y eventualmente a un fallo. Unbound 1.25.1 contiene un parche con una corrección para desduplicar las opciones EDNS y una corrección para evitar la truncación del cálculo del tamaño del campo EDNS.
CVE Modified by redhat-SADP7/14/2026 10:21:38 PM
Action
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Affected
[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 8)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:8::appstream"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::appstream"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::crb"]},{"vendor":"Red Hat","product":"Red Hat Hardened Images","defaultStatus":"affected","cpes":["cpe:/a:redhat:hummingbird:1"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]}]
[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound","cpes":["cpe:/o:redhat:enterprise_linux:10.2"],"versions":[{"version":"0:1.24.2-7.el10_2.1","lessThan":"*","versionType":"rpm","status":"unaffected"}]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound","cpes":["cpe:/a:redhat:enterprise_linux:8"],"versions":[{"version":"0:1.16.2-5.11.el8_10","lessThan":"*","versionType":"rpm","status":"unaffected"}]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound","cpes":["cpe:/a:redhat:enterprise_linux:9"],"versions":[{"version":"0:1.24.2-3.el9_8.1","lessThan":"*","versionType":"rpm","status":"unaffected"}]},{"vendor":"Red Hat","product":"Red Hat Hardened Images","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound-main","cpes":["cpe:/a:redhat:hummingbird:1"],"versions":[{"version":"1.25.1-0.1.hum1","lessThan":"*","versionType":"rpm","status":"unaffected"}]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"unbound","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"rhcos","cpes":["cpe:/a:redhat:openshif
[{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 8)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:8::appstream"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux AppStream (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::appstream"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:10.2"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)","defaultStatus":"affected","cpes":["cpe:/a:redhat:enterprise_linux:9::crb"]},{"vendor":"Red Hat","product":"Red Hat Hardened Images","defaultStatus":"affected","cpes":["cpe:/a:redhat:hummingbird:1"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 6","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:6"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 7","defaultStatus":"affected","cpes":["cpe:/o:redhat:enterprise_linux:7"]},{"vendor":"Red Hat","product":"Red Hat OpenShift Container Platform 4","defaultStatus":"affected","cpes":["cpe:/a:redhat:openshift:4"]}]
New CVE Received from NLnet Labs5/20/2026 6:16:27 AM
Action
Type
Old Value
New Value
Added
Description
NLnet Labs Unbound 1.14.0 up to and including version 1.25.0 has a vulnerability that results in heap overflow when encoding multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options in the reply packet. The relevant options ('nsid', 'answer-cookie', 'pad-responses' (default)) need to be enabled for the vulnerability to be exploited. An adversary who can query Unbound can exploit the vulnerability by attaching multiple NSID and/or DNS Cookie EDNS and/or EDNS Padding options to the query. A flaw in the size calculation of the EDNS field truncates the correct value which allows the encoder to overflow the available space when writing. Those two combined lead to a heap overflow write of Unbound controlled data and eventually a crash. Unbound 1.25.1 contains a patch with a fix to de-duplicate the EDNS options and a fix to prevent truncation of the EDNS field size calculation.
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