etcd: `tlsListener.acceptLoop` spawns unbounded handshake goroutines with no deadline
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.7epss 0.7%
exploitation probability
0.7%top 49% of all CVEs
observed exploitation
nono source reports it
etcd is a distributed key-value store for the data of a distributed system. Prior to versions 3.5.33, 3.6.14, and 3.7.1, a network attacker who can reach an etcd TLS listener can open many TCP connections and never send a ClientHello. In client/pkg/transport/listener_tls.go, each connection handled by tlsListener.acceptLoop spawns a goroutine that blocks indefinitely inside tls.Conn.Handshake() and remains tracked in the pending map. Unbounded goroutine and map growth can exhaust memory in the etcd process, causing loss of availability for the cluster and, when etcd backs Kubernetes, the control plane. This issue is fixed in versions 3.5.33, 3.6.14, and 3.7.1.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
etcd-io · etcdReferences
https://github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2https://github.com/etcd-io/etcd/commit/89ff6d50796049d4f1136915ba21504b76e7e372https://github.com/etcd-io/etcd/commit/8e4dd0679a2c6b095d2a32a749fda2521c7809a3https://github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057https://github.com/etcd-io/etcd/pull/22130https://github.com/etcd-io/etcd/releases/tag/v3.5.33https://github.com/etcd-io/etcd/releases/tag/v3.6.14https://github.com/etcd-io/etcd/releases/tag/v3.7.1https://github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3