CVE-2026-5503— out-of-bounds write in TLSX_EchChangeSNI via attacker-controlled publicName
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I. Basic Information for CVE-2026-5503
Vulnerability Information
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Vulnerability Title
out-of-bounds write in TLSX_EchChangeSNI via attacker-controlled publicName
Source: NVD (National Vulnerability Database)
Vulnerability Description
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.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
跨界内存写
Source: NVD (National Vulnerability Database)
Vulnerability Title
wolfSSL（CyaSSL） 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
wolfSSL（CyaSSL）是美国wolfSSL公司的一个针对嵌入式系统开发人员使用的小的、可移植的嵌入式SSL编程库。 wolfSSL（CyaSSL）存在安全漏洞，该漏洞源于TLSX_EchChangeSNI函数无条件设置扩展，可能导致将攻击者控制的publicName附加到共享的WOLFSSL_CTX并触发越界写入。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-5503
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Same Patch Batch · wolfSSL · 2026-04-09 · 16 CVEs total
| CVE-2026-5263 | URI nameConstraints not enforced in ConfirmNameConstraints() | |
| CVE-2026-5187 | Heap Out-of-Bounds Write in DecodeObjectId() in wolfSSL | |
| CVE-2026-5264 | DTLS 1.3 ACK heap buffer overflow | |
| CVE-2026-5295 | Stack Buffer Overflow in wolfSSL PKCS7 wc_PKCS7_DecryptOri() via Oversized OID | |
| CVE-2026-5393 | OOB Read in DoTls13CertificateVerify with WOLFSSL_DUAL_ALG_CERTS | |
| CVE-2026-5446 | wolfSSL ARIA-GCM TLS 1.2/DTLS 1.2 GCM nonce reuse | |
| CVE-2026-5504 | PKCS7 CBC Padding Oracle — Plaintext Recovery | |
| CVE-2026-5447 | Heap buffer overflow in CertFromX509() via AuthorityKeyIdentifier | |
| CVE-2026-5778 | Integer underflow leads to out-of-bounds access in sniffer ChaCha decrypt path. | |
| CVE-2026-5772 | MatchDomainName 1-Byte Stack Buffer Over-Read in Hostname Validation | |
| CVE-2026-5507 | Session Cache Restore — Arbitrary Free via Deserialized Pointer | |
| CVE-2026-5194 | wolfSSL ECDSA Certificate Verification | |
| CVE-2026-5392 | wolfSSL heap OOB read in PKCS7 SignedData streaming | |
| CVE-2026-5460 | Heap Use-After-Free in PQC Hybrid KeyShare Error Cleanup in wolfSSL TLS 1.3 | |
| CVE-2026-5448 | 1-2 Byte Buffer Overflow in wolfSSL_X509_notAfter/notBefore |
IV. Related Vulnerabilities
Same product: wolfSSL
- CVE-2026-5477
Prefix-substitution forgery via integer overflow in wolfCryp - CVE-2026-5188
Integer underflow in X.509 SAN parsing in wolfSSL - CVE-2026-5500
Improper Validation of AES-GCM Authentication Tag Length in - CVE-2026-5501
Improper Certificate Signature Verification in X.509 Chain V - CVE-2026-5466
wc_VerifyEccsiHash missing sanity check
Same vendor: wolfSSL
- CVE-2026-0930
Potential wolfSSHd Buffer out-of-bounds Read on Windows Hand - CVE-2026-5477
Prefix-substitution forgery via integer overflow in wolfCryp - CVE-2026-5188
Integer underflow in X.509 SAN parsing in wolfSSL - CVE-2026-5500
Improper Validation of AES-GCM Authentication Tag Length in - CVE-2026-5501
Improper Certificate Signature Verification in X.509 Chain V
V. Comments for CVE-2026-5503
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