CVE-2020-15093
Improper verification of signature threshold in tough
The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic signatures. It allows an attacker to duplicate a valid signature in order to circumvent TUF requiring a minimum threshold of unique signatures before the metadata is considered valid. A fix is available in version 0.7.1. CVE-2020-6174 is assigned to the same vulnerability in the TUF reference implementation.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Improper verification of signature threshold in tough
The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic signatures. It allows an attacker to duplicate a valid signature in order to circumvent TUF requiring a minimum threshold of unique signatures before the metadata is considered valid. A fix is available in version 0.7.1. CVE-2020-6174 is assigned to the same vulnerability in the TUF reference implementation.
- Record
CVE-2020-15093- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2021-1579
The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic signatures. It allows an attacker to duplicate a valid signature in order to circumvent TUF requiring a minimum threshold of unique signatures before the metadata is considered valid. A fix is available in version 0.7.1. CVE-2020-6174 is assigned to the same vulnerability in the TUF reference implementation.
- Record
EUVD-2021-1579- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-5q2r-92f9-4m49
Improper verification of signature threshold in tough
Impact
The tough library, prior to 0.7.1, does not properly verify the uniqueness of keys in the signatures provided to meet the threshold of cryptographic signatures. It allows someone with access to a valid signing key to create multiple valid signatures in order to circumvent TUF requiring a minimum threshold of unique keys before the metadata is considered valid.
AWS would like to thank Erick Tryzelaar of the Google Fuchsia Team for reporting this issue.
Patches
A fix is available in version 0.7.1.
Workarounds
No workarounds to this issue are known.
References
CVE-2020-6174 is assigned to the same issue in the TUF reference implementation.
https://github.com/theupdateframework/tuf/pull/974 https://nvd.nist.gov/vuln/detail/CVE-2020-6174
For more information
If you have any questions or comments about this advisory, contact AWS Security at [email protected].
- Record
GHSA-5q2r-92f9-4m49- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
NVD
The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic signatures. It allows an attacker to duplicate a valid signature in order to circumvent TUF requiring a minimum threshold of unique signatures before the metadata is considered valid. A fix is available in version 0.7.1. CVE-2020-6174 is assigned to the same vulnerability in the TUF reference implementation.
- Record
CVE-2020-15093- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:P/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
OSV
The tough library (Rust/crates.io) prior to version 0.7.1 does not properly verify the threshold of cryptographic signatures. It allows an attacker to duplicate a valid signature in order to circumvent TUF requiring a minimum threshold of unique signatures before the metadata is considered valid. A fix is available in version 0.7.1. CVE-2020-6174 is assigned to the same vulnerability in the TUF reference implementation.
- Record
CVE-2020-15093- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-07
OSVGHSA-5q2r-92f9-4m49
Improper verification of signature threshold in tough
Impact
The tough library, prior to 0.7.1, does not properly verify the uniqueness of keys in the signatures provided to meet the threshold of cryptographic signatures. It allows someone with access to a valid signing key to create multiple valid signatures in order to circumvent TUF requiring a minimum threshold of unique keys before the metadata is considered valid.
AWS would like to thank Erick Tryzelaar of the Google Fuchsia Team for reporting this issue.
Patches
A fix is available in version 0.7.1.
Workarounds
No workarounds to this issue are known.
References
CVE-2020-6174 is assigned to the same issue in the TUF reference implementation.
https://github.com/theupdateframework/tuf/pull/974 https://nvd.nist.gov/vuln/detail/CVE-2020-6174
For more information
If you have any questions or comments about this advisory, contact AWS Security at [email protected].
- Record
GHSA-5q2r-92f9-4m49- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
OSVRUSTSEC-2020-0024
Improper uniqueness verification of signature threshold
The tough library, prior to 0.7.1, does not properly verify the uniqueness of keys in the signatures provided to meet the threshold of cryptographic signatures. It allows someone with access to a valid signing key to create multiple valid signatures in order to circumvent TUF requiring a minimum threshold of unique keys before the metadata is considered valid.
AWS would like to thank Erick Tryzelaar of the Google Fuchsia Team for reporting this issue.
A fix is available in version 0.7.1.
CVE-2020-6174 is assigned to the same issue in the TUF reference implementation.
If you have any questions or comments about this advisory, contact AWS Security at [email protected].
- Record
RUSTSEC-2020-0024- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-15093 is a high vulnerability (CVSS 8.6) in Amazon Tough, published July 9, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.36%, the 71st percentile. Fixed in tough 0.7.1.
References
github.com/awslabs/tough/security/advisories/GHSA-5q2r-92f9-4m49
crates.io/crates/tough
nvd.nist.gov/vuln/detail/CVE-2020-15093
rustsec.org/advisories/RUSTSEC-2020-0024.html