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Description

Out-of-bounds write in the Renesas TSIP TLS 1.3 transcript buffer. In tsip_StoreMessage() the capacity check guarding the fixed message bag (MSGBAG_SIZE) sets an error code but fails to return, so execution falls through to an XMEMCPY that writes past the end of the buffer once the accumulated TLS 1.3 handshake transcript exceeds MSGBAG_SIZE (8 KB), corrupting adjacent heap state and potentially causing a remote denial of service crash. The bag is sized to hold a normal handshake, so this is reached only by an unusually large but valid certificate chain, or by a malicious or man-in-the-middle server sending an oversized handshake message to a client that does not strictly verify the chain. This only affects builds using the Renesas TSIP TLS port (WOLFSSL_RENESAS_TSIP_TLS) as a TLS 1.3 client on Renesas MCUs with TSIP hardware enabled, and is rated High within those builds. All other configurations are unaffected.

PUBLISHED Reserved 2026-06-17 | Published 2026-06-25 | Updated 2026-06-26 | Assigner wolfSSL




HIGH: 8.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N

Problem types

CWE-787 Out-of-bounds Write

CWE-393 Return of Wrong Status Code

Product status

Default status
unaffected

5.4.0 (semver)
affected

Credits

NVIDIA Project Vanessa finder

References

github.com/wolfSSL/wolfssl/pull/10705 patch

www.wolfssl.com/docs/security-vulnerabilities/

cve.org (CVE-2026-55958)

nvd.nist.gov (CVE-2026-55958)

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