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CVE-2026-52731 medium CVSS 6.5

Vulnerability in zebra-rpc (CVE-2026-52731)

Summary

Vulnerability in zebra-rpc (CVE-2026-52731). Risk of unauthorized operations or information disclosure. Exploitable via zebrad. Mitigation: upgrade to 8.0.0 or later.

Original description

The description as published by the source.

Am I affected

You are affected if:

  1. You run zebrad up to and including v4.4.1.
  2. Your zebrad.toml sets rpc.listen_addr to a TCP address (RPC server is enabled).
  3. 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.

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 ASC…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-52731 has been found in zebra-rpc.
Attackers can target a specific entry point like zebrad over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade zebra-rpc to 8.0.0 or later.
If unsure, ask your IT team or search "zebra-rpc CVE-2026-52731" on the vendor's site.

CVE-2026-52731 (zebra-rpc) — CWE-248 / CVSS v3 6.5
Attack vector: remote (network-reachable) / no user interaction
Attack surface: zebrad / zebrad.toml / rpc.listen_addr / getblocktemplate
Patched: 8.0.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-248) exists in zebra-rpc. Attackers reach the vulnerable code path via zebrad.

📍 Affected scope

Check the vendor advisory for the affected versions of zebra-rpc. Attack surface: zebrad / zebrad.toml / rpc.listen_addr / getblocktemplate.

🔥 Severity

Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 8.0.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'zebra-rpc' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'zebra-rpc' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で zebra-rpc を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade zebra-rpc to 8.0.0

    ステージング環境で 8.0.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

rust zebra-rpc
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.0.0"}]}]
rust zebrad
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.0"}]}]
crates.io zebra-rpc
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"8.0.0"}]}]
crates.io zebrad
[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.5.0"}]}]

References

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