GHSA-QV2R-V3MX-F4PF
Vulnerability from github – Published: 2026-07-02 19:28 – Updated: 2026-07-02 19:28Am I affected
You are affected if:
- You run
zebradup to and includingv4.4.1. - Your
zebrad.tomlsetsrpc.listen_addrto a TCP address (RPC server is enabled). - An attacker can authenticate to the RPC endpoint. With the default
enable_cookie_auth = true, this requires the attacker to read the.cookiefile. Withenable_cookie_auth = false, any network client reaching the RPC port can trigger it.
Summary
The getblocktemplate RPC handler panics when parsing a LongPollId parameter that contains non-ASCII (multi-byte UTF-8) characters. The handler performs byte-index string slicing on the user-supplied string, which panics in Rust when a byte index falls within a multi-byte character boundary. Because Zebra's release profile sets panic = "abort", the panic terminates the entire node process.
Details
The getblocktemplate handler receives a user-supplied LongPollId string and slices it at fixed byte offsets to extract the encoded tip hash and tip height. When the string contains multi-byte UTF-8 characters, a byte-index slice can land in the middle of a character, causing Rust's str indexing to panic with "byte index is not a char boundary."
Under the panic = "abort" release profile, this panic terminates the entire zebrad process rather than just the RPC task.
Patches
zebra-rpc 8.0.0 and zebrad 4.5.0.
Replace byte-index string slicing with character-aware parsing or validate that the LongPollId string contains only ASCII characters before slicing.
Workarounds
- Disable the RPC server by removing
rpc.listen_addrfromzebrad.toml. - Ensure
enable_cookie_auth = true(the default) and restrict filesystem access to the.cookiefile. - Place a reverse proxy in front of the RPC port that validates
LongPollIdparameters are ASCII-only before forwarding.
Impact
A single authenticated RPC request terminates the zebrad process. Same impact profile as GHSA-c8w6-x74f-vmg3: repeatable on restart, affects mining pools and infrastructure that forward getblocktemplate calls.
Credit
Reported by @sangsoo-osec via a private GitHub Security Advisory submission.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 7.0.0"
},
"package": {
"ecosystem": "crates.io",
"name": "zebra-rpc"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.0.0"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.4.1"
},
"package": {
"ecosystem": "crates.io",
"name": "zebrad"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.5.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-52731"
],
"database_specific": {
"cwe_ids": [
"CWE-248"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-02T19:28:03Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Am I affected\n\nYou are affected if:\n\n1. You run `zebrad` up to and including `v4.4.1`.\n2. Your `zebrad.toml` sets `rpc.listen_addr` to a TCP address (RPC server is enabled).\n3. An attacker can authenticate to the RPC endpoint. With the default `enable_cookie_auth = true`, this requires the attacker to read the `.cookie` file. With `enable_cookie_auth = false`, any network client reaching the RPC port can trigger it.\n\n### Summary\n\nThe `getblocktemplate` RPC handler panics when parsing a `LongPollId` parameter that contains non-ASCII (multi-byte UTF-8) characters. The handler performs byte-index string slicing on the user-supplied string, which panics in Rust when a byte index falls within a multi-byte character boundary. Because Zebra\u0027s release profile sets `panic = \"abort\"`, the panic terminates the entire node process.\n\n### Details\n\nThe `getblocktemplate` handler receives a user-supplied `LongPollId` string and slices it at fixed byte offsets to extract the encoded tip hash and tip height. When the string contains multi-byte UTF-8 characters, a byte-index slice can land in the middle of a character, causing Rust\u0027s `str` indexing to panic with \"byte index is not a char boundary.\"\n\nUnder the `panic = \"abort\"` release profile, this panic terminates the entire `zebrad` process rather than just the RPC task.\n\n### Patches\n\nzebra-rpc 8.0.0 and zebrad 4.5.0.\n\nReplace byte-index string slicing with character-aware parsing or validate that the `LongPollId` string contains only ASCII characters before slicing.\n\n### Workarounds\n\n- Disable the RPC server by removing `rpc.listen_addr` from `zebrad.toml`.\n- Ensure `enable_cookie_auth = true` (the default) and restrict filesystem access to the `.cookie` file.\n- Place a reverse proxy in front of the RPC port that validates `LongPollId` parameters are ASCII-only before forwarding.\n\n### Impact\n\nA single authenticated RPC request terminates the `zebrad` process. Same impact profile as GHSA-c8w6-x74f-vmg3: repeatable on restart, affects mining pools and infrastructure that forward `getblocktemplate` calls.\n\n### Credit\n\nReported by `@sangsoo-osec` via a private GitHub Security Advisory submission.",
"id": "GHSA-qv2r-v3mx-f4pf",
"modified": "2026-07-02T19:28:03Z",
"published": "2026-07-02T19:28:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-qv2r-v3mx-f4pf"
},
{
"type": "PACKAGE",
"url": "https://github.com/ZcashFoundation/zebra"
},
{
"type": "WEB",
"url": "https://github.com/ZcashFoundation/zebra/blob/d4cd662c716382f6397d2a730148025a1ca79fec/Cargo.toml#L305"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "zebrad has full node denial of service via non-ASCII LongPollId in getblocktemplate"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.