ZcashFoundation Zebra up to 5.x Mempool is_valid denial of service

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.3$0-$5k1.03+

Summaryinfo

A vulnerability marked as problematic has been reported in ZcashFoundation Zebra up to 5.x. This impacts the function CachedFfiTransaction::is_valid of the component Mempool. The manipulation leads to denial of service. This vulnerability is documented as CVE-2026-104431. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in ZcashFoundation Zebra up to 5.x. It has been rated as problematic. This issue affects the function CachedFfiTransaction::is_valid of the component Mempool. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-104431 since 10/02/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 6.0.0 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (VulnCheck): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Zebra 6.0.0

Timelineinfo

10/02/2026 Advisory disclosed
10/02/2026 +0 days CVE reserved
10/02/2026 +0 days VulDB entry created
10/02/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-104431 (🔒)
GCVE (CVE): GCVE-0-2026-104431
GCVE (VulDB): GCVE-100-413081

Entryinfo

Created: 10/02/2026 14:14
Changes: 10/02/2026 14:14 (77)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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