CVE-2026-52731Network attack vector

Authenticated node crash via UTF-8 slicing

Published Aug 18, 2026 · Updated Aug 18, 2026

Denial of service in Zcash Foundation Zebra before 4.5.0 allows remote authenticated users to crash the node via a crafted LongPollId. The zebra-rpc getblocktemplate handler passes the user-supplied LongPollId to LongPollId::from_str, which slices fixed byte ranges from a UTF-8 string after checking only total byte length; a slice that lands inside a multibyte character panics with a char-boundary error. Reachability requires an enabled RPC listener and valid RPC authentication unless cookie auth is disabled; because release builds set panic to abort, one malformed request terminates the entire zebrad process and can be repeated after restart.

CVSS severity6.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Zcash Foundation Zebra before 4.5.0 allows remote authenticated users to crash the node via a crafted LongPollId. The zebra-rpc getblocktemplate handler passes the user-supplied LongPollId to LongPollId::from_str, which slices fixed byte ranges from a UTF-8 string after checking only total byte length; a slice that lands inside a multibyte character panics with a char-boundary error. Reachability requires an enabled RPC listener and valid RPC authentication unless cookie auth is disabled; because release builds set panic to abort, one malformed request terminates the entire zebrad process and can be repeated after restart.

The record

CVE
CVE-2026-52731
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Zcash Foundation
Product
Zebra
Classifications
CWE-248, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 4.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zcash Foundation · Zebraversion=< 4.5.0
Zcash Foundation · zebra-rpcversion=< 8.0.0

Published CVSS scores

6.5GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-248Uncaught Exception
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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