CVE-2026-104432

Zebra before 6.3.0 False Readiness via Discarded One-Hash FindBlocks Response

MEDIUM
5.3
CVSS Score
Published: October 2, 2026 at 11:38 AM UTC
Updated: October 6, 2026 at 03:17 AM UTC
2 products affected across 2 vendorsZebraZebra

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

Zebra before 6.3.0 contains an improper exceptional condition check in ChainSync::obtain_tips that discards valid one-hash FindBlocks responses, falsely reporting close-to-tip status. Peers returning only the next block hash cause a zero-length sync sample, making the /ready endpoint return 200 OK while the node remains behind the tip.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

95%
v < 6.3.0
Affected range stops below 6.3.0, so it looks safe — our inference, not a vendor statement
v < 6.3.0
Vendor states this is fixed in 6.3.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-754

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