CVE-2026-129217
bgpd: out-of-bounds heap read and crash on NOTIFICATION Cease/Hard Reset with one data byte
In FRRouting (FRR) 8.3 through 10.5.1, bgp_notify_decapsulate_hard_reset() in bgpd/bgp_packet.c does not validate the length of the data field of a received BGP NOTIFICATION Cease/Hard Reset message (RFC 8538). When the data field is exactly one byte long, the function reads one byte past the end of a heap buffer and the 16-bit length of the encapsulated data underflows to 65535, causing a 65535-byte out-of-bounds heap read followed by an assertion failure. A remote BGP peer that has established a session and negotiated the Graceful Restart capability with the Notification (N) bit can send such a message to crash the bgpd daemon, terminating all BGP sessions (denial of service). This is fixed in 10.0.5, 10.1.5, 10.2.6, 10.3.4, 10.4.3, 10.5.2 and 10.6.0.
Fixes and workarounds
Fix
Upgrade to a fixed version of FRRouting
Source: CNA: NetDEFWorkaround
Graceful Restart Capability needs to be enabled. Disable the Capability with "no bgp graceful-restart notification" or "bgp graceful-restart-disable"
Source: CNA: NetDEFFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: NetDEFAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| FRRouting FRRouting |
≥ 10.5.0; < 10.5.2 (affected, semver) ≥ 10.4.0; < 10.4.3 (affected, semver) ≥ 10.3; < 10.3.4 (affected, custom) ≥ 10.2; < 10.2.6 (affected, custom) ≥ 10.1; < 10.1.5 (affected, custom) ≥ 8.3; < 10.0.5 (affected, custom) ≥ 0; < 8.3 (unaffected, custom) Other versions: unaffected |
CNA: NetDEF |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.0 medium |
CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N | CNA: NetDEF |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/FRRouting/frr/issues/20793CNA: NetDEF · issue-tracking
- https://github.com/FRRouting/frr/pull/20796CNA: NetDEF · patch
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