How severe is CVE-2026-104423?

CVE-2026-104423 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-104423 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-104423?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-104423 published?

CVE-2026-104423 was published on 2026-10-02.

CVE-2026-104423

CVE-2026-104423 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-405.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-405
Published: 2026-10-02
Last modified: 2026-10-02

Description

Zebra (zebrad) before 6.2.1 contains an asymmetric resource consumption vulnerability that allows unauthenticated peers to stall block verification by pushing V6 mempool transactions with invalid Halo2 proofs. Attackers can flood the shared unprioritized Halo2 verification queue with zero-fee transactions carrying zero-filled Orchard and Ironwood proofs, causing nodes to fall behind the chain tip.

Frequently asked questions

What is CVE-2026-104423?: Zebra (zebrad) before 6.2.1 contains an asymmetric resource consumption vulnerability that allows unauthenticated peers to stall block verification by pushing V6 mempool transactions with invalid Halo2 proofs. Attackers can flood the shared unprioritized Halo2 verification queue with zero-fee transactions carrying zero-filled Orchard and Ironwood proofs, causing nodes to fall behind the chain tip.
How severe is CVE-2026-104423?: CVE-2026-104423 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-104423 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-104423?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-104423 published?: CVE-2026-104423 was published on 2026-10-02.

References

Other CWE-405 vulnerabilities

CVE-2025-53633 — Critical (CVSS 9.8): Chall-Manager is a platform-agnostic system able to start Challenges on Demand of a player. When decoding a scenario…
CVE-2021-38447 — High (CVSS 8.6): OCI OpenDDS versions prior to 3.18.1 are vulnerable when an attacker sends a specially crafted packet to flood target…
CVE-2025-42874 — High (CVSS 7.9): SAP NetWeaver remote service for Xcelsius allows an attacker with network access and high privileges to execute…
CVE-2026-104712 — High (CVSS 7.5): Asymmetric resource consumption (amplification) vulnerability in Apache Struts. When a request parameter is bound to an…
CVE-2026-104431 — High (CVSS 7.5): Zebra before 6.0.0 contains a denial of service vulnerability that allows unauthenticated peers to stall Tokio workers…
CVE-2026-103880 — High (CVSS 7.5): Asymmetric Resource Consumption vulnerability in Apache Directory LDAP API. Storing a password using the bcrypt…

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