CVE-2026-63448: Suricata smb: some SMB flows can cause resource exhaustion

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-18 · updated 2026-09-28
Weakness: CWE-400

Description

Suricata is a network Intrusion Detection System, Intrusion Prevention System and Network Security Monitoring engine. Prior to 7.0.17 and 8.0.6, the SMB parser can retain force-completed transactions on flows where Suricata sees payload in only one direction, including async-oneside flows, because cleanup waits for inspection in the unseen direction. The transaction creation paths in rust/src/smb can exceed the intended SMB_MAX_TX bound, and cleanup repeatedly scans the growing list. Sustained one-directional SMB traffic can therefore cause unbounded per-flow state and CPU and memory exhaustion. This issue is fixed in versions 8.0.6 and 7.0.17.

Affected products

OISF suricata: before 7.0.17; from 8.0.0 before 8.0.6 — fixed in 7.0.17, 8.0.6

How to fix

Upgrade to a fixed version: OISF suricata 7.0.17, 8.0.6. Check the vendor advisory for mitigations.

References

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