--- title: "CVE-2026-67277: Kernel memory disclosure and denial… | CubePath" description: "RouterOS accepts a \"related\" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use…" language: en source: https://cubepath.com/security/cve/CVE-2026-67277 --- # CVE-2026-67277: Kernel memory disclosure and denial… | CubePath ## Description RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel. This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable) Official description from the CVE record, published by CERT-PL. Copyright © 1999-2026 The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CVE license. [View the record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-67277) ## Key data ### CVSS 4.0 High 8.8 Score published by CERT-PL in the CVE record. CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N | Metric | Value | What it means | | ----------------------------------- | ------- | --------------------------------------------------------------------------------------------------------------- | | Attack vector | Network | The vulnerable component can be reached over a network, possibly from the Internet. | | Attack complexity | Low | No measurable action is needed to get around the system's built-in security controls. The attack is repeatable. | | Attack requirements | None | The attack works without any special deployment or execution conditions. | | Privileges required | None | No account or privileges are needed. | | User interaction | None | No action from any user is needed. | | Vulnerable system: confidentiality | Low | Limited effect on the secrecy of data. | | Vulnerable system: integrity | None | No effect on the trustworthiness of data. | | Vulnerable system: availability | High | Serious or total effect on availability. | | Subsequent systems: confidentiality | None | No effect on other systems' data secrecy. | | Subsequent systems: integrity | None | No effect on other systems' data trustworthiness. | | Subsequent systems: availability | None | No effect on other systems' availability. | CVSS is owned and managed by FIRST.Org, Inc. (FIRST) and is used by permission. Each CVSS score on this site is shown together with its vector string, as published in the CVE record by the source named next to it. Learn more at [first.org/cvss](https://www.first.org/cvss/) . ### EPSS Exploit Prediction Scoring System by FIRST: an estimate of the probability that exploitation activity will be observed in the next 30 days. Score 0.01560 (1.6% probability) Percentile 75.4% Scores of Nov 10, 2026 Model v2026.06.15 ### CISA Known Exploited Vulnerabilities This CVE is listed in the CISA KEV catalog. Name in the catalog MikroTik RouterOS Missing Authentication for Critical Function Vulnerability Added to the catalog Sep 10, 2026 Federal due date Sep 13, 2026 ### CISA assessment as of Sep 8, 2026 Stakeholder-Specific Vulnerability Categorization (SSVC) decision points added by CISA. Exploitation Recorded by CISA as active Automatable yes Technical impact partial ### Weakness (CWE) CWE catalog version 5.0. CWE names: Copyright © 2006-2026, The MITRE Corporation. See [/security/cve/legal](https://cubepath.com/security/cve/legal) for the CWE license. - [CWE-306](https://cwe.mitre.org/data/definitions/306.html) Missing Authentication for Critical Functionality ## Affected products Products listed in the CVE record, as the CNA published them. - Mikrotik RouterOS - affected: 7.24 up to before 7.24.2 - affected: 7.0.0 up to before 7.23.4 - affected: 6.0.0 up to before 6.49.21 ## References Links listed in the CVE record. They lead to other sites, which CubePath does not control. - [cert.pl/en/posts/2026/09/mikrotik-routeros-cve](https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve) third-party-advisory - [cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-router…](https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/) technical-description - [npratley.net/reversing-mikrotiks-silent-patch-the-routeros-…](https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/) exploit - [mikrotik.com/supportsec/september-2026-vulnerability](https://mikrotik.com/supportsec/september-2026-vulnerability/) vendor-advisory - [forum.mikrotik.com/t/6-49-21-long-term-is-released/272802](https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802) release-notes - [forum.mikrotik.com/t/7-23-4-long-term-is-released/272801](https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801) release-notes - [forum.mikrotik.com/t/7-24-2-stable-is-released/272800](https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800) release-notes ## Timeline 1. ID reserved Jul 29, 2026 2. Record published Sep 5, 2026 3. Added to CISA KEV Sep 10, 2026 4. Record last updated Sep 11, 2026 ## Look up another CVE ## About CubePath CubePath is a cloud provider with data centers in Europe and the United States. It offers VPS, bare metal servers and DDoS protection. [Cloud VPS](https://cubepath.com/vps) [DDoS protection](https://cubepath.com/ddos-protection) Data from the CVE Program (MITRE), CISA KEV and FIRST EPSS. CVSS is owned by FIRST and used by permission. Not affiliated with or endorsed by MITRE, CISA or FIRST. Data as of Nov 10, 2026, 19:08 UTC. [Sources and licenses](https://cubepath.com/security/cve/legal)