CVE-2026-120033frrouting reachable assertion
CVE-2026-120033 is a reachable assertion in frrouting, rated medium (6.0 on CVSS 4.0).
Why this priority: Medium severity, with no exploitation signal.
Published · Updated · NVD status: Awaiting Analysis
What it is
Input can trigger an assertion that stops the process.
How it is reached
An attacker can exploit it over the network, with an ordinary user account, and nobody has to click anything. Success also depends on conditions the attacker does not fully control.
What an attacker gains
A successful attack can take it offline. In practice, this kind of flaw lets an attacker exhaust CPU, memory or connections until the service stops answering. The damage can spread past the vulnerable component into others.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- No fixed version is listed yet. Find every place frrouting runs, watch the references for a fix, and plan a replacement if it is no longer supported.
- While there is no fix, review who holds accounts that can reach it.
Description from NVD
In FRRouting 10.1 and later, bgpd does not correctly close a BGP session when the Send Hold Timer (RFC 9687) expires, i.e. when a neighbor has stopped accepting data from the router for twice the hold time. The connection is closed, but bgpd still considers the session to be up.
A BGP neighbor that keeps sending KEEPALIVEs but stops reading from its connection, at a time when the router has a large amount of data to send to it (for example while sending it a full routing table), can cause one of the following:
* If the neighbor announced Graceful Restart support: bgpd crashes shortly after the session is closed (after the neighbor's announced restart time plus one keepalive interval), taking down all BGP sessions on the router. The neighbor can repeat this each time bgpd restarts. * Otherwise: the session stays stuck in the Established state. The neighbor's routes stay installed and keep being advertised to other peers, and the neighbor cannot reconnect until an operator runs "clear bgp <neighbor>".
The neighbor does not need to be malicious; an overloaded or stuck peer can trigger the same behavior.
Required configuration: no special configuration is needed. Any BGP neighbor with an established session can trigger the issue under default settings, for example:
router bgp 65001 neighbor 192.0.2.2 remote-as 65002
Graceful Restart helper mode, which leads to the crash, is enabled by default. With default timers (keepalive 60s, hold time 180s), the session is closed about 6 minutes after the neighbor stops reading.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Public entry points and shared services that must stay up. The flaw sits between untrusted traffic and shared capacity.
Trust boundaries in play
- Authenticated network access. An account is needed, so exposure follows who can sign in: customers, partners or staff.
- Isolation between components. The impact crosses out of the vulnerable component into others it should be isolated from.
- Between untrusted traffic and shared capacity. An attacker who crosses it can exhaust CPU, memory or connections until the service stops answering.
Questions to answer about your own systems
- Where does frrouting run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.