CVE-2026-52731

ZEBRA: Full node denial of service via non-ASCII LongPollId in getblocktemplate

Published Aug 18, 2026 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description
ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, an attacker authenticated to an enabled Zebra RPC endpoint can terminate zebrad by supplying a getblocktemplate LongPollId containing multi-byte UTF-8 characters. In zebra-rpc/src/methods/types/long_poll.rs, LongPollId::from_str originally checked the input byte length and then sliced fixed byte ranges to parse encoded fields. A slice boundary can land inside a multi-byte character and trigger Rust's byte index is not a char boundary panic. Zebra release builds use panic equals abort, so one malformed authenticated RPC request terminates the entire node process and can be repeated after restart. This issue is fixed in version 4.5.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-qv2r-v3mx-f4pf zebrad has full node denial of service via non-ASCII LongPollId in getblocktemplate
History
Type Values Removed Values Added
First Time appeared Zcashfoundation
Zcashfoundation zebra
Zcashfoundation zebra-rpc
Vendors & Products Zcashfoundation
Zcashfoundation zebra
Zcashfoundation zebra-rpc
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description ZEBRA is a Zcash node written entirely in Rust. Prior to 4.5.0, an attacker authenticated to an enabled Zebra RPC endpoint can terminate zebrad by supplying a getblocktemplate LongPollId containing multi-byte UTF-8 characters. In zebra-rpc/src/methods/types/long_poll.rs, LongPollId::from_str originally checked the input byte length and then sliced fixed byte ranges to parse encoded fields. A slice boundary can land inside a multi-byte character and trigger Rust's byte index is not a char boundary panic. Zebra release builds use panic equals abort, so one malformed authenticated RPC request terminates the entire node process and can be repeated after restart. This issue is fixed in version 4.5.0.
Title ZEBRA: Full node denial of service via non-ASCII LongPollId in getblocktemplate
Weaknesses CWE-248
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 18, 2026, 7:42 PM
Reserved
Jun 8, 2026, 2:00 PM
Status
Deferred
Published
Aug 18, 2026, 8:17 PM
Modified
Nov 9, 2026, 8:10 PM