Description
Buffer overflow in the cluster_process_heartbeat function in cluster.c in layer 2 tunneling protocol network server (l2tpns) before 2.1.21 allows remote attackers to cause a denial of service via a large heartbeat packet.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | l2tpns | 2.1.21-1 | — |
| Debian 13 | l2tpns | 2.1.21-1 | — |
| Debian 12 | l2tpns | 2.1.21-1 | — |
| Debian 3.1 | l2tpns | 2.0.14-1sarge1 | DSA-1230-1 |
Advisories 1
- DSA-1230-1 l2tpns Debian Security (DSA / DLA) · Mar 9, 2026
References
- 23333 third-party-advisory
- http://sourceforge.net/project/shownotes.php?group_id=97282&release_id=468202
- 23230 third-party-advisory
- http://l2tpns.cvs.sourceforge.net/l2tpns/l2tpns/cluster.c?r1=1.53&r2=1.54
- l2tpns-heartbeat-dos(30732) vdb-entry
- DSA-1230 vendor-advisory
- ADV-2006-4860 vdb-entry
- 21443 vdb-entry