etcd: `tlsListener.acceptLoop` spawns unbounded handshake goroutines with no deadline
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 3.5.33, 3.6.14, 3.7.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- etcd-io etcd
fixed in 3.5.33; From 3.6.0 · fixed in 3.6.14; From 3.7.0-alpha.0 · fixed in 3.7.1
- go.etcd.io/etcd/v3Go
From 3.7.0-alpha.0 · fixed in 3.7.1
- go.etcd.io/etcd/v3Go
From 3.6.0 · fixed in 3.6.14
- go.etcd.io/etcd/v3Go
fixed in 3.5.33
- go.etcd.io/etcd/client/pkg/v3Go
fixed in 3.5.33; From 3.6.0 · fixed in 3.6.14; From 3.7.0-alpha.0 · fixed in 3.7.1