CVE-2026-5503
In TLSX_EchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSX_Find returned NULL. This caused TLSX_UseSNI to attach the attacker-controlled publicName to the shared WOLFSSL_CTX when no inner SNI was configured. TLSX_EchRestoreSNI then failed to clean it up because its removal was gated on serverNameX != NULL. The inner ClientHello was sized before the pollution but written after it, causing TLSX_SNI_Write to memcpy 255 bytes past the allocation boundary.
- Affected products
- Wolfssl
- Wolfssl
- ≤ 5.9.0
- CVSS 3.1
- 9.1 CRITICAL
- EPSS
- 0.4% (32th percentile)
- Weakness
- CWE-787
- NVD status
- Analyzed
- Published
- 2026-04-09
CVE-2026-5503 at NVD
No indexed exploits for CVE-2026-5503 yet
Our index is partial: it proves presence, never absence
No exploit for CVE-2026-5503 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.