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CVE-2026-123554VulnerabilityPublished

Zebra zebrad 6.4.0 before 7.0.0 performs quadratic work in the mempool coinbase-maturity check because

Source GCVE Database

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Authoritative record:CVE-2026-123554· High 8.7

Not known to be exploited · CVSS 8.7 High : upgrade to 7.0.0 soon.

Data as of 8 Nov 2026, 06:36 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (VulnCheck)CVSS 4.08.7
CNA (VulnCheck)CVSS 3.17.5
Patch
Available – fixed in 7.0.0
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 7 Nov 2026.

What to do

Upgrade zebra to 7.0.0.

Affected software

ProductAffectedFixed in
ZcashFoundationzebraAffected
  • >=6.4.0 <7.0.0
Fixed in
  • 7.0.0
crates.iozebrapkg:cargo/zebraOther threatsAffected
  • >=6.4.0 <7.0.0
Fixed in
  • 7.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, operators should consider limiting connections or rate-limiting transaction submissions from peers to mitigate potential resource exhaustion.

Description

Zebra zebrad versions 6.4.0 up to but not including 7.0.0 contain a vulnerability where the mempool coinbase-maturity check performs quadratic work. This occurs because the function Transaction::coinbase_spend_restriction() rebuilds the transaction's output list repeatedly for each spent outpoint. An attacker can exploit this by sending many unsigned transactions with numerous transparent inputs and outputs, causing excessive CPU usage and pinning verification threads without incurring a misbehavior score.

References

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