# CVE-2026-34202: zebrad DoS — Fixed in 4.3.0 🦀 crates.io Not in CISA KEV # CVE-2026-34202 — zebrad CVE-2026-34202 is a Code Injection vulnerability in zebrad. A fix is available for zebrad — see the affected versions and patch details below. Zebra node crash — V5 transaction hash panic (P2P reachable) Also known as[GHSA-qp6f-w4r3-h8wg](/vulnerability/GHSA-qp6f-w4r3-h8wg) Published Mar 31, 2026 Updated Oct 28, 2026 Affected 2 pkgs Patched 2 / 2 Exploits None indexed Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS) ## Exploitation Status ### No confirmed exploitation observed yet - CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks. - CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment. Exploitation and automatability from CISA’s SSVC triage for CVE-2026-34202. ## EPSS Exploitation Probability [via FIRST.org ↗](https://www.first.org/epss/) 0.8%probability of exploitation in next 30 days Lower Risk0.00% Lower risk than most CVEs56th percentile — riskier than 56% of all scored CVEsHighest risk 0.00%0.48%0.95%1.43%0.1%0.8%May 26Sep 26Nov 26 Probability of exploitation in the next 30 days, from [FIRST.org EPSS](https://www.first.org/epss/). ## Real-World Exposure 2 pkgs affected 🦀`zebrad`🦀`zebra-chain` Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems. ## Description * * * ## Remote Denial of Service via Crafted V5 Transactions ### Summary A vulnerability in Zebra's transaction processing logic allows a remote, unauthenticated attacker to cause a Zebra node to panic (crash). This is triggered by sending a specially crafted V5 transaction that passes initial deserialization but fails during transaction ID calculation. ### Severity **Critical** - This is a Remote Denial of Service (DoS) that requires no authentication and can be triggered by a single network message. ### Affected Versions All Zebra versions supporting V5 transactions (Network Upgrade 5 and later) prior to **version 4.3.0**. ### Description The vulnerability stems from Zebra lazily validating transaction fields that are eagerly validated in the librustzcash parsing logic used when Zebra computes transaction ids and auth digests for V5 transactions where Zebra panics if those computations fail. `PushTransaction` messages with malformed V5 transactions are successfully deserialized as the zebra-chain `Transaction` type by the network codec, but when Zebra converts those transactions into internal types to compute the TxID expecting it to succeed, it triggers a panic/crash. An attacker can trigger this crash by sending a single crafted `tx` message to a Zebra node's public P2P port. The same issue can be triggered via the `sendrawtransaction` RPC method. ### Impact **Remote Denial of Service** - **Attack Vector:** Remote, unauthenticated. - **Effect:** Immediate crash of the Zebra node. - **Scope:** Any node with an open P2P port (default 8233) or exposed RPC interface is vulnerable. ### Fixed Versions This issue is fixed in **Zebra 4.3.0**. The fix ensures that any transaction that would fail TxID calculation is rejected during the initial deserialization phase, and replaces internal panics with graceful error handling. ### Mitigation Users should upgrade to **Zebra 4.3.0** or later immediately. If an immediate upgrade is not possible, users should ensure their RPC port is not exposed to the Internet. However, the P2P port must remain closed or restricted to trusted peers to fully mitigate the risk, which may impact the node's ability to sync with the network. ### Credits Zebra thanks [robustfengbin](https://github.com/robustfengbin), who discovered this issue and reported it via coordinated disclosure process. * * * ## Affected Packages 2 total 2 fixed Ecosystem Package Vulnerable range Fix 🦀crates.io `zebrad` all versions 4.3.0`cargo update -p zebrad --precise 4.3.0` 🦀crates.io `zebra-chain` all versions 6.0.1`cargo update -p zebra-chain --precise 6.0.1` ## Affected Products 2 products · 2 configurations Application `zebra`zfnd < 4.3.0 range Application `zebra-chain`zfnd < 6.0.1 range ## Detection & mitigation playbook Open-source dependency 1. ### Detect Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for zebrad, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version. 2. ### Fix Update zebrad to 4.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-34202 is resolved across your whole dependency graph. 3. ### Workarounds Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. ## Frequently Asked Questions \--- # Remote Denial of Service via Crafted V5 Transactions ## Summary A vulnerability in Zebra's transaction processing logic allows a remote, unauthenticated attacker to cause a Zebra node to panic (crash). This is triggered by sending a specially crafted V5 transaction that passes initial deserialization but fails during transaction ID calculation. ## Severity \*\*Critical\*\* - This is a Remote Denial of Service (DoS) that requires no authentication and can be triggered by a single network message. ## Affected Versions All Zebra versions supporting V5 transactions (Network Upgrade 5 and lat O3 Security · Impact-Aware SCA ### Is CVE-2026-34202 in your dependencies? Find it across crates.io, including transitive dependencies. [Scan my dependencies](/book-demo) [How O3 SCA works](/impact-aware-sca)