CVE-2023-42448
Hydra's contestation period in head datum can be modified during Close transaction, allowing malicious participant to freely modify the contestation deadline
CVE-2023-42448 is a high vulnerability (CVSS 8.1) in Input-output-hk Hydra, published October 4, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.98%, the 62nd percentile. No source names a fixed version.
Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, the specification states that the contestation period in the datum of the UTxO at the head validator must stay unchanged as the state progresses from Open to Closed (Close transaction), but no such check appears to be performed in the checkClose function of the head validator. This would allow a malicious participant to modify the contestation deadline of the head to either allow them to fanout the head without giving another participant the chance to contest, or prevent any participant from ever redistributing the funds locked in the head via a fan-out. Version 0.13.0 contains a patch for this issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Hydra's contestation period in head datum can be modified during Close transaction, allowing malicious participant to freely modify the contestation deadline
Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, the specification states that the contestation period in the datum of the UTxO at the head validator must stay unchanged as the state progresses from Open to Closed (Close transaction), but no such check appears to be performed in the checkClose function of the head validator. This would allow a malicious participant to modify the contestation deadline of the head to either allow them to fanout the head without giving another participant the chance to contest, or prevent any participant from ever redistributing the funds locked in the head via a fan-out. Version 0.13.0 contains a patch for this issue.
- Record
CVE-2023-42448- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2023-46894
Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, the specification states that the contestation period in the datum of the UTxO at the head validator must stay unchanged as the state progresses from Open to Closed (Close transaction), but no such check appears to be performed in the checkClose function of the head validator. This would allow a malicious participant to modify the contestation deadline of the head to either allow them to fanout the head without giving another participant the chance to contest, or prevent any participant from ever redistributing the funds locked in the head via a fan-out. Version 0.13.0 contains a patch for this issue.
- Record
EUVD-2023-46894- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-03
NVD
Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, the specification states that the contestation period in the datum of the UTxO at the head validator must stay unchanged as the state progresses from Open to Closed (Close transaction), but no such check appears to be performed in the checkClose function of the head validator. This would allow a malicious participant to modify the contestation deadline of the head to either allow them to fanout the head without giving another participant the chance to contest, or prevent any participant from ever redistributing the funds locked in the head via a fan-out. Version 0.13.0 contains a patch for this issue.
- Record
CVE-2023-42448- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-20, CWE-1284
- Updated
- 2026-11-02
OSV
Hydra's contestation period in head datum can be modified during Close transaction, allowing malicious participant to freely modify the contestation deadline
Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, the specification states that the contestation period in the datum of the UTxO at the head validator must stay unchanged as the state progresses from Open to Closed (Close transaction), but no such check appears to be performed in the checkClose function of the head validator. This would allow a malicious participant to modify the contestation deadline of the head to either allow them to fanout the head without giving another participant the chance to contest, or prevent any participant from ever redistributing the funds locked in the head via a fan-out. Version 0.13.0 contains a patch for this issue.
- Record
CVE-2023-42448- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases, products, published | EUVD |
| 2026-11-02 | created | CVE List, NVD, OSV |
References
github.com/input-output-hk/hydra/security/advisories/GHSA-mgcx-6p7h-5996
nvd.nist.gov/vuln/detail/CVE-2023-42448