Ubuntu Linux CVE-2026-52062

MEDIUM

2026-08-13 vendor:ubuntu

Severity by source

vuln.today AI

6.5 MEDIUM

Adjacent network vector (link-local only), no privileges or user interaction needed, availability impact only - no confidentiality or integrity effect indicated.

3.1 AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

4.0 AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Estimated by vuln.today — no official severity rating has been published for this CVE yet.

Lifecycle Timeline

Analysis Generated

Aug 13, 2026 - 17:40 vuln.today

CVE Published

Aug 13, 2026 - 00:00 cve.org

MEDIUM

DescriptionCVE.org

[NDP RA allows any value for MTU]

AnalysisAI

Ubuntu's IPv6 network stack fails to validate the MTU value carried in NDP Router Advertisement (RA) messages, allowing any arbitrary MTU value to be accepted by the host. An attacker with the ability to send crafted IPv6 RA packets on the local network segment can set an excessively low or malformed MTU, disrupting IPv6 connectivity or causing packet-handling anomalies. No CVSS score, CWE classification, KEV listing, or POC has been provided at time of analysis, so severity and exploitability remain unconfirmed.

Technical ContextAI

Neighbor Discovery Protocol (NDP) is the IPv6 equivalent of ARP, defined in RFC 4861. Router Advertisement (RA) messages sent by routers include optional fields such as the MTU option (type 5), which advises hosts of the link MTU. RFC 4861 and RFC 8200 specify that IPv6 hosts must not use an MTU below 1280 bytes. If a receiving host's NDP implementation does not bounds-check or validate the MTU value in received RA messages, a crafted RA with an out-of-spec MTU (e.g., 0, 1, or an absurdly large value) could be accepted and applied to the interface. This likely resides in the Linux kernel's IPv6 NDP RA processing code within the net/ipv6 subsystem, affecting Ubuntu as a downstream distributor. No CWE was provided; the root cause class appears closest to CWE-20 (Improper Input Validation) or CWE-1284 (Improper Validation of Specified Quantity in Input).

Affected ProductsAI

The vulnerability is reported by Ubuntu (vendor:ubuntu) and affects Ubuntu Linux systems running with IPv6 enabled and NDP Router Advertisement processing active. The exact affected Ubuntu versions, kernel versions, and corresponding CPE strings are not provided in the available intelligence. Administrators should monitor Ubuntu Security Notices (USN) at ubuntu.com/security/notices for the authoritative affected-version list and patch details.

RemediationAI

No vendor-released patch version has been confirmed in the available data. Administrators should monitor Ubuntu Security Notices for a USN advisory addressing CVE-2026-52062. As an interim compensating control, deploying RA Guard (IEEE 802.1aq / RFC 6105) on managed network switches will drop unauthorized RA messages at the switch port level, preventing untrusted hosts from injecting crafted RA packets - this is the most effective mitigation for link-local NDP attacks. Alternatively, disabling IPv6 on interfaces where it is not operationally required eliminates exposure entirely, though this may break IPv6-dependent services. On Linux hosts, the kernel parameter 'net.ipv6.conf.all.accept_ra' can be set to 0 via sysctl to stop processing RA messages, but this will also prevent legitimate router configuration and may disrupt IPv6 connectivity. Each workaround should be tested in a staging environment before production deployment.