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Affected Vendors & Products
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Solution
No solution given by the vendor.
Workaround
Do not configure "neighbor <peer-group> soo" on a peer-group used by "bgp listen range". Instead, set the SoO extended community with an inbound route-map, or set "neighbor soo" on statically configured neighbors. Configuring a TCP-MD5 "password" on the peer-group limits the trigger to hosts that know the key.
Fri, 13 Nov 2026 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | frr: bgpd double free of peer-group Site-of-Origin when dynamic neighbors disconnect | |
| First Time appeared |
Frrouting
Frrouting frrouting |
|
| Weaknesses | CWE-415 CWE-416 |
|
| CPEs | cpe:2.3:a:frrouting:frrouting:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Frrouting
Frrouting frrouting |
|
| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: NetDEF
Published:
Updated: 2026-11-13T11:54:24.035Z
Reserved: 2026-10-31T18:17:02.102Z
Link: CVE-2026-120221
No data.
Status : Received
Published: 2026-11-13T12:17:03.210
Modified: 2026-11-13T12:17:03.210
Link: CVE-2026-120221
No data.
OpenCVE Enrichment
No data.