Vulnerability · Published Apr 9, 2026 · Assigned by wolfSSL
CVE-2026-5460Heap Use-After-Free in PQC Hybrid KeyShare Error Cleanup in wolfSSL TLS 1.3
Medium 6.3
In plain English
A medium-severity use-after-free 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 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
A heap use-after-free exists in wolfSSL's TLS 1.3 post-quantum cryptography (PQC) hybrid KeyShare processing. In the error handling path of TLSX_KeyShare_ProcessPqcHybridClient() in src/tls.c, the inner function TLSX_KeyShare_ProcessPqcClient_ex() frees a KyberKey object upon encountering an error. The caller then invokes TLSX_KeyShare_FreeAll(), which attempts to call ForceZero() on the already-freed KyberKey, resulting in writes of zero bytes over freed heap memory.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2026-5460 |
| Alpine:v3.24 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2026-5460 |
| Debian:12 | wolfssl | no fix listed | DEBIAN-CVE-2026-5460 |
| Debian:13 | wolfssl | no fix listed | DEBIAN-CVE-2026-5460 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5460 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5460 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-5460 |
| Ubuntu:26.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5460 |
| Ubuntu:26.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-5460 |
Affected products (as reported)
Weakness: CWE-416 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N