CVE-2026-5460

EUVD-2026-21240
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.5 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
Base Score
CVSS 3.x
EPSS Score
Percentile: 16%
Affected Products (NVD)
VendorProductVersion
wolfsslwolfssl
𝑥
< 5.9.1
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
wolfssl
bookworm
no-dsa
bullseye
postponed
forky
5.9.1-0.1
fixed
sid
5.9.1-0.1
fixed
trixie
no-dsa
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
wolfssl
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
questing
needs-triage
resolute
needs-triage
xenial
ignored