Vulnerability · Published Jul 17, 2023 · Assigned by wolfSSL
CVE-2023-3724TLS 1.3 client issue handling malicious server when not including a KSE and PSK extension
Critical 9.1
In plain English
A critical-severity improper input validation in wolfSSL from wolfSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 51% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | wolfssl | 5.6.2-r0 | ALPINE-CVE-2023-3724 |
| Alpine:v3.21 | wolfssl | 5.6.2-r0 | ALPINE-CVE-2023-3724 |
| Alpine:v3.22 | wolfssl | 5.6.2-r0 | ALPINE-CVE-2023-3724 |
| Alpine:v3.23 | wolfssl | 5.6.2-r0 | ALPINE-CVE-2023-3724 |
| Alpine:v3.24 | wolfssl | 5.6.2-r0 | ALPINE-CVE-2023-3724 |
| Debian:12 | wolfssl | 5.5.4-2+deb12u1 | DEBIAN-CVE-2023-3724 |
| Debian:13 | wolfssl | 5.5.4-2.1 | DEBIAN-CVE-2023-3724 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2023-3724 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2023-3724 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2023-3724 |
| Ubuntu:26.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2023-3724 |
| Ubuntu:26.10 | wolfssl | no fix listed | UBUNTU-CVE-2023-3724 |
Affected products (as reported)
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H