GHSA-52xf-5p2m-9wrv
s2n-tls has a potentially observable differences in RSA premaster secret handling
When receiving a message from a client that sent an invalid RSA premaster secret, an issue in s2n-tls results in the server performing additional processing when the premaster secret contains an incorrect client hello version. While no practical attack on s2n-tls has been demonstrated, this causes a small timing difference which could theoretically be used as described in the Marvin Attack [1].
We would like to thank Hubert Kario [2] for reporting this issue.
Impact
The extent of this issue is a timing difference. No practical attack on s2n-tls has been demonstrated.
This issue affects server applications that permit RSA key exchange. Applications that use the default, built-in blinding feature or properly implement self-service blinding are not affected.
Impacted versions: <= v1.4.15.
Patches
The patch is included in v1.4.16 [3].
Workarounds
Applications can work around this issue by using an s2n-tls security policy that disallows RSA key exchange.
If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page [4] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
[1] https://people.redhat.com/~hkario/marvin/ [2] https://github.com/tomato42 [3] https://github.com/aws/s2n-tls/releases/tag/v1.4.16 [4] https://aws.amazon.com/security/vulnerability-reporting
What each source reports
GitHub AdvisoriesNo score
s2n-tls has a potentially observable differences in RSA premaster secret handling
When receiving a message from a client that sent an invalid RSA premaster secret, an issue in s2n-tls results in the server performing additional processing when the premaster secret contains an incorrect client hello version. While no practical attack on s2n-tls has been demonstrated, this causes a small timing difference which could theoretically be used as described in the Marvin Attack [1].
We would like to thank Hubert Kario [2] for reporting this issue.
Impact
The extent of this issue is a timing difference. No practical attack on s2n-tls has been demonstrated.
This issue affects server applications that permit RSA key exchange. Applications that use the default, built-in blinding feature or properly implement self-service blinding are not affected.
Impacted versions: <= v1.4.15.
Patches
The patch is included in v1.4.16 [3].
Workarounds
Applications can work around this issue by using an s2n-tls security policy that disallows RSA key exchange.
If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page [4] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
[1] https://people.redhat.com/~hkario/marvin/ [2] https://github.com/tomato42 [3] https://github.com/aws/s2n-tls/releases/tag/v1.4.16 [4] https://aws.amazon.com/security/vulnerability-reporting
- Record
GHSA-52xf-5p2m-9wrv- Weakness
- CWE-203
- Updated
- 2026-11-02
OSVNo score
s2n-tls has a potentially observable differences in RSA premaster secret handling
When receiving a message from a client that sent an invalid RSA premaster secret, an issue in s2n-tls results in the server performing additional processing when the premaster secret contains an incorrect client hello version. While no practical attack on s2n-tls has been demonstrated, this causes a small timing difference which could theoretically be used as described in the Marvin Attack [1].
We would like to thank Hubert Kario [2] for reporting this issue.
Impact
The extent of this issue is a timing difference. No practical attack on s2n-tls has been demonstrated.
This issue affects server applications that permit RSA key exchange. Applications that use the default, built-in blinding feature or properly implement self-service blinding are not affected.
Impacted versions: <= v1.4.15.
Patches
The patch is included in v1.4.16 [3].
Workarounds
Applications can work around this issue by using an s2n-tls security policy that disallows RSA key exchange.
If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page [4] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.
[1] https://people.redhat.com/~hkario/marvin/ [2] https://github.com/tomato42 [3] https://github.com/aws/s2n-tls/releases/tag/v1.4.16 [4] https://aws.amazon.com/security/vulnerability-reporting
- Record
GHSA-52xf-5p2m-9wrv- Weakness
- CWE-203
- Updated
- 2026-11-02
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
GHSA-52xf-5p2m-9wrv is a vulnerability with no CVSS score yet in s2n-tls, published June 6, 2024. No source lists public exploit code. Fixed in s2n-tls 0.2.7.