CVE-2026-104431

Zebra before 6.0.0 Denial of Service via Synchronous Script FFI Verification

State: Published
Severity: 8.7 High
Published: Oct 2, 2026
Updated: Oct 2, 2026
Reserved: Oct 2, 2026

Description

Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers by submitting mempool transactions requiring expensive synchronous script verification. Attackers can send non-standard high-sigop P2SH transactions that reach CachedFfiTransaction::is_valid() before standardness checks, saturating the verifier buffer and rendering the node unresponsive.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	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	VulnCheck
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	VulnCheck

Weaknesses

CWE-405 Asymmetric Resource Consumption (Amplification)

Affected Products

Product	Versions
zebraZcashFoundation	before 6.0.0Affected 6.0.0Not affected

References

GitHub Security Advisory (GHSA-84j3-rw4c-gqmj)vendor-advisory
VulnCheck Advisory: Zebra before 6.0.0 Denial of Service via Synchronous Script FFI Verificationthird-party-advisory

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