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Response snapshot Oct 30, 2026, 23:06 UTC

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VulnerabilityCVE-2026-62162

Hydra is a layer-two scalability solution for Cardano.

Hydra is a layer-two scalability solution for Cardano. Prior to 2.1.0, the Claim branch in hydra-plutus/validators/deposit.ak checks only that datum.head_id matches the attacker-controlled redeemer.currencySymbol and that the transaction is valid before the deposit deadline.

At a glance

Exploited
Not known
Severity
8.2 High (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-62162 (opens a new tab)

What happened

Hydra is a layer-two scalability solution for Cardano. Prior to 2.1.0, the Claim branch in hydra-plutus/validators/deposit.ak checks only that datum.head_id matches the attacker-controlled redeemer.currencySymbol and that the transaction is valid before the deposit deadline. It neither requires spending the Head state-token UTxO in the same transaction nor constrains outputs.

After a deposit made through POST /commit is confirmed, any third party able to build a Cardano transaction can observe and consume the pending deposit UTxO before its deadline and redirect the assets to an arbitrary address. A standalone deposit spend invokes no Head validator, bypassing its safety checks; historical head-ID binding and the Aiken rewrite retained this missing invariant.

The default deadline is three times depositPeriod, so the described attack applies to pending deposits before that deadline. This issue is fixed in version 2.1.0.

Scores and how they were measured

CVSS base severity

8.2

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-62162 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Hydra is a layer-two scalability solution for Cardano. (CVE-2026-62162). https://kevwire.com/record/CVE-2026-62162

MLA

"Hydra is a layer-two scalability solution for Cardano. (CVE-2026-62162)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-62162.

Chicago

KEVWire. "Hydra is a layer-two scalability solution for Cardano. (CVE-2026-62162)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-62162.

Evidence summary (plain text)

Hydra is a layer-two scalability solution for Cardano. (Oct 30, 2026).
Hydra is a layer-two scalability solution for Cardano. Prior to 2.1.0, the Claim branch in hydra-plutus/validators/deposit.ak checks only that datum.head_id matches the attacker-controlled redeemer.currencySymbol and that the transaction is valid before the deposit deadline. It neither requires spending the Head state-token UTxO in the same transaction nor constrains outputs.
CVSS 8.2 (version 4.0; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-62162).
Sources:
NVD CVE-2026-62162: https://nvd.nist.gov/vuln/detail/CVE-2026-62162
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T19:16:05.328Z&lastModEndDate=2026-10-30T20:45:56.257Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T18:46:05.049Z&lastModEndDate=2026-10-30T20:15:57.059Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T18:10:59.199Z&lastModEndDate=2026-10-30T19:45:55.485Z&resultsPerPage=500&startIndex=500
Record ID: CVE-2026-62162.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 20:45 UTC. Ingestion is not an independent editorial investigation.

NVD status: Deferred. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail