What’s Vulnerable › Vulnerabilities

CVE-2026-52731: ZEBRA: Full node denial of service via non-ASCII LongPollId in getblocktemplate

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-09-09
• Weakness: CWE-248

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.

Affected products

• ZcashFoundation zebra-rpc: before 8.0.0
• ZcashFoundation zebra: before 4.5.0

References

• https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd
• https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0
• https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-qv2r-v3mx-f4pf

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