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Medium

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

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-52731
Confirmed fixed CVEs
Not specified
Updated in this feed
7 Nov 2026, 20:33 UTC · Revision 1

Source evidence

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

core-osv · Original source

Published 18 Aug 2026, 19:25 UTC

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.

osv:CVE-2026-52731
Complete source record
{
  "id": "468cf95f0c8e27de6036a5a3488b9831444b87a8beab5489bbcf267a01d038f4",
  "url": "https://osv.dev/vulnerability/CVE-2026-52731",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "ZEBRA: Full node denial of service via non-ASCII LongPollId in getblocktemplate",
    "summary": "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.",
    "evidence": "osv:CVE-2026-52731",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-52731",
      "aliases": [
        "CVE-2026-52731",
        "GHSA-qv2r-v3mx-f4pf"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zcashfoundation/zebra",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1440b43ca7df59aca948090d45117557b217a6cd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.5.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1440b43ca7df59aca948090d45117557b217a6cd"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1440b43ca7df59aca948090d45117557b217a6cd"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v4.5.0"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.5.0"
                      }
                    ],
                    "source": "DESCRIPTION"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.4.0",
            "v4.4.1",
            "v4.3.1",
            "4.3.1",
            "v4.3.0",
            "v4.2.0",
            "v4.1.0",
            "v4.0.0",
            "v3.1.0",
            "v3.0.0",
            "v3.0.0-rc.0",
            "v2.5.0",
            "v2.0.1",
            "v2.4.2",
            "v2.3.0",
            "v2.4.0",
            "v2.0.0",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0-rc.0",
            "v1.9.0",
            "v1.8.0",
            "v1.7.0",
            "v1.6.1",
            "v1.6.0",
            "v1.5.2",
            "v1.5.1",
            "v1.5.0",
            "v1.4.0",
            "v1.3.0",
            "v1.2.0",
            "v1.1.0",
            "v1.0.1",
            "v1.0.0",
            "v1.0.0-rc.9",
            "v1.0.0-rc.8",
            "v1.0.0-rc.7",
            "v1.0.0-rc.6",
            "v1.0.0-rc.5",
            "v1.0.0-rc.0",
            "v1.0.0-rc.4",
            "v1.0.0-rc.3",
            "v1.0.0-rc.2",
            "v1.0.0-rc.1",
            "v1.0.0-beta.15",
            "v1.0.0-beta.14",
            "v1.0.0-beta.13",
            "v1.0.0-beta.12",
            "v1.0.0-beta.11",
            "v1.0.0-beta.10",
            "v1.0.0-beta.9",
            "v1.0.0-beta.8",
            "v1.0.0-beta.7",
            "v1.0.0-beta.6",
            "v1.0.0-beta.5",
            "v1.0.0-beta.4",
            "v1.0.0-beta.3",
            "v1.0.0-beta.2",
            "v1.0.0-beta.1",
            "v1.0.0-beta.0",
            "v1.0.0-alpha.19",
            "v1.0.0-alpha.18",
            "v1.0.0-alpha.17",
            "v1.0.0-alpha.16",
            "v1.0.0-alpha.15",
            "v1.0.0-alpha.14",
            "v1.0.0-alpha.13",
            "v1.0.0-alpha.12",
            "v1.0.0-alpha.11",
            "v1.0.0-alpha.10",
            "v1.0.0-alpha.9",
            "v1.0.0-alpha.8",
            "v1.0.0-alpha.7",
            "v1.0.0-alpha.6",
            "v1.0.0-alpha.5",
            "v1.0.0-alpha.4",
            "v1.0.0-alpha.3",
            "v1.0.0-alpha.2",
            "v1.0.0-alpha.1",
            "v1.0.0-alpha.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-52731.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.442937504Z",
      "provider": "osv",
      "references": [
        "https://github.com/ZcashFoundation/zebra/releases/tag/v4.5.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52731.json",
        "https://github.com/ZcashFoundation/zebra/security/advisories/GHSA-qv2r-v3mx-f4pf",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-52731",
        "https://github.com/ZcashFoundation/zebra/commit/1440b43ca7df59aca948090d45117557b217a6cd"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-248"
        ],
        "cna_assigner": "GitHub_M",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "8.0.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/52xxx/CVE-2026-52731.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-52731",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520322,
  "published_at": "2026-08-18T19:25:39.314+00:00"
}