etcd's WAL `ReadAll` method vulnerable to an entry with large index causing panic

MEDIUM 6.5CVE-2020-15106 · CVE-2020-15112 · BIT-etcd-2020-15106 · Published 05/08/2020 · updated 17/06/2026

In short

CVE-2020-15106 is a MEDIUM (CVSS 6.5) vulnerability affecting go.etcd.io/etcd, go.etcd.io/etcd/v3, etcd (etcd).
Chance of exploitation in the next 30 days (EPSS): 1.3%, higher than 69.6% of all vulnerabilities.
Fix: update to 0.5.0-alpha.5.0.20200423152442-f4b650b51dc4, 3.4.10, 3.3.23 or later.

Package	Affected versions	Patched versions
go.etcd.io/etcd Go	`< 0.5.0-alpha.5.0.20200423152442-f4b650b51dc4`	`0.5.0-alpha.5.0.20200423152442-f4b650b51dc4`
go.etcd.io/etcd/v3 Go	`≥ 3.4.0, < 3.4.10< 3.3.23`	`3.4.103.3.23`
etcd etcd	`≥ 3.4.0, < 3.4.10< 3.3.23`	`3.4.103.3.23`

Description

Vulnerability type

Data Validation

Detail

In the ReadAll method in wal/wal.go, it is possible to have an entry index greater then the number of entries. This could cause issues when WAL entries are being read during consensus as an arbitrary etcd consensus participant could go down from a runtime panic when reading the entry.

References

Find out more on this vulnerability in the security audit report

For more information

If you have any questions or comments about this advisory:

Contact the etcd security committee

NVD description

In etcd before versions 3.3.23 and 3.4.10, a large slice causes panic in decodeRecord method. The size of a record is stored in the length field of a WAL file and no additional validation is done on this data. Therefore, it is possible to forge an extremely large frame size that can unintentionally panic at the expense of any RAFT participant trying to decode the WAL.