CVE-2026-120221
What it is
In FRRouting 8.4 and later, bgpd frees the same memory twice when dynamic BGP neighbors disconnect, if the peer-group used by a "bgp listen range" also has a Site-of-Origin configured ("neighbor PG soo"). Each dynamic neighbor shares the peer-group's SoO value instead of getting its own copy, but frees it as its own when the neighbor is deleted, which happens as soon as its connection closes. The first disconnect leaves the peer-group pointing at freed memory, and the second disconnect frees it again, causing bgpd to abort and drop all BGP sessions on the router. Any host whose address falls inside the listen range can trigger this by opening and closing two TCP connections to the BGP port, without sending any BGP message and without knowing the AS number, and can repeat it each time bgpd restarts. If the peer-group has a TCP-MD5 password, only hosts that know the password can trigger it. Two ordinary flaps of legitimate dynamic neighbors have the same effect. Between the two frees, displaying the configuration ("show running-config") or establishing a dynamic neighbor also reads the freed memory, which can crash bgpd after a single disconnect. Only configurations that combine a listen range with a SoO on the same peer-group are affected.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- ReservedThe CVE id was reserved by its CNA
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: not scored yet.
- Severity: 8.2 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Weakness
- CWE-415
- Record status
- Received
Attack profile CVSS 4.0 · 8.2
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:N/R:A/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-120221.md and follow it. Check whether this project is affected by CVE-2026-120221. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
