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.
Metrics
Affected Vendors & Products
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Advisories
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Fixes
Solution
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Workaround
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References
| Link | Providers |
|---|---|
| https://github.com/wolfSSL/wolfssl/pull/10102 |
|
History
Thu, 09 Apr 2026 22:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | out-of-bounds write in TLSX_EchChangeSNI via attacker-controlled publicName | |
| Weaknesses | CWE-787 | |
| References |
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| Metrics |
cvssV4_0
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Projects
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MITRE
Status: PUBLISHED
Assigner: wolfSSL
Published:
Updated: 2026-04-09T22:35:39.437Z
Reserved: 2026-04-03T15:55:20.740Z
Link: CVE-2026-5503
Vulnrichment
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NVD
Status : Received
Published: 2026-04-09T23:17:01.257
Modified: 2026-04-09T23:17:01.257
Link: CVE-2026-5503
Redhat
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OpenCVE Enrichment
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Weaknesses