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MikroTik RouterOS Labelled-VPN NLRI Prefix-Length Underflow Holds the BGP Plane Down Indefinitely; Fix Is Only in a Development Build

Last refreshed2026-09-29

Status: NEW  |  Advisory ID: CVE-2026-93345

Key Details

CVECVE-2026-93345
CVSS Score / Version7.5 (High) / CVSS v3.1
Updated2026-09-25
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Proseattack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is none; integrity impact is none; availability impact is high.
Classified asCWE-1284 (Improper Validation of Specified Quantity in Input)

What to Know

MikroTik RouterOS before 7.25beta4 contains an improper input validation vulnerability in the labelled-VPN NLRI iterators of the routing service that allows an unauthenticated on-path attacker to crash the BGP service by sending a malformed MP_REACH_NLRI UPDATE message with a prefix-length value below the minimum valid for a labelled-VPN NLRI, which passes validation while describing a route with a negative-length address portion. Attackers can repeatedly send a single BGP UPDATE packet carrying a VPNv4 or VPNv6 NLRI with an out-of-bounds prefix-length to indefinitely hold down the BGP plane, causing session termination without a NOTIFICATION and triggering a service malfunction on the device. The fix is carried only in 7.25beta4, a development build; the current stable release 7.24.2 and the current long-term release 7.23.5 both remain affected. (NVD)

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-93345
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-93345