Vulnerability · Published Aug 12, 2026 · Assigned by GitHub_M
CVE-2026-73500etcd: `tlsListener.acceptLoop` spawns unbounded handshake goroutines with no deadline
High 8.7
In plain English
A high-severity resource allocation without limits in etcd from etcd-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | etcd | no fix listed | DEBIAN-CVE-2026-73500 |
| Debian:13 | etcd | no fix listed | DEBIAN-CVE-2026-73500 |
| Debian:14 | etcd | no fix listed | DEBIAN-CVE-2026-73500 |
| Go | go.etcd.io/etcd/client/pkg/v3 | 3.5.33, 3.6.14, 3.7.1 | GO-2026-6107 |
| Go | go.etcd.io/etcd/v3 | 3.5.33 | GHSA-6vch-q96h-7gc3 |
| Go | go.etcd.io/etcd/v3 | 3.6.14 | GHSA-6vch-q96h-7gc3 |
| Go | go.etcd.io/etcd/v3 | 3.7.1 | GHSA-6vch-q96h-7gc3 |
| Ubuntu:26.10 | etcd | no fix listed | UBUNTU-CVE-2026-73500 |
Affected products (as reported)
Weakness: CWE-770 · Vector: 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
References
- https://github.com/etcd-io/etcd/security/advisories/GHSA-6vch-q96h-7gc3 x_refsource_CONFIRM
- https://github.com/etcd-io/etcd/pull/22130 x_refsource_MISC
- https://github.com/etcd-io/etcd/commit/2e07efce9745004eb4773cffaada9b5cdf77cff2 x_refsource_MISC
- https://github.com/etcd-io/etcd/commit/89ff6d50796049d4f1136915ba21504b76e7e372 x_refsource_MISC
- https://github.com/etcd-io/etcd/commit/8e4dd0679a2c6b095d2a32a749fda2521c7809a3 x_refsource_MISC
- https://github.com/etcd-io/etcd/commit/f73cba7d920019f91a1ea1f6697833e42731f057 x_refsource_MISC
- https://github.com/etcd-io/etcd/releases/tag/v3.5.33 x_refsource_MISC
- https://github.com/etcd-io/etcd/releases/tag/v3.6.14 x_refsource_MISC
- https://github.com/etcd-io/etcd/releases/tag/v3.7.1 x_refsource_MISC