# CVE-2023-3724: wolfssl: If a TLS 1.3 client gets neither a PSK (pre shared key) extension nor a KSE (key share extension) when connecting to...

CVE-2023-3724 is fixed in wolfssl on 1 platform, first by DEBIAN-CVE-2023-3724, released July 17, 2023. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2023-3724
- Priority: High
- CVSS: 8.8 (high)
- EPSS: 0.0065
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 17, 2023

## Description

If a TLS 1.3 client gets neither a PSK (pre shared key) extension nor a KSE (key share extension) when connecting to a malicious server, a default predictable buffer gets used for the IKM (Input Keying Material) value when generating the session master secret. Using a potentially known IKM value when generating the session master secret key compromises the key generated, allowing an eavesdropper to reconstruct it and potentially allowing access to or meddling with message contents in the session. This issue does not affect client validation of connected servers, nor expose private key information, but could result in an insecure TLS 1.3 session when not controlling both sides of the connection. wolfSSL recommends that TLS 1.3 client side users update the version of wolfSSL used.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | wolfssl Debian 12.15 (bookworm) | 5.5.4-2+deb12u1 | [DEBIAN-CVE-2023-3724](https://patchblox.com/security/data/fix/linux/debian-cve-2023-3724.md) | Jul 17, 2023 |
| Linux | wolfssl Debian 13.5 (trixie) | 5.5.4-2.1 | [DEBIAN-CVE-2023-3724](https://patchblox.com/security/data/fix/linux/debian-cve-2023-3724.md) | Jul 17, 2023 |

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