CVE-2026-55958
Renesas TSIP TLS 1.3 transcript buffer out-of-bounds write in tsip_StoreMessage
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.
INFO
Published Date :
June 25, 2026, 7:35 p.m.
Last Modified :
June 25, 2026, 7:35 p.m.
Remotely Exploit :
Yes !
Source :
wolfSSL
Affected Products
The following products are affected by CVE-2026-55958
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | 50d2cd11-d01a-48ed-9441-5bfce9d63b27 |
Solution
- Update the Renesas TSIP TLS implementation.
- Apply patches for the tsip_StoreMessage() function.
- Ensure strict certificate chain verification.
- Validate handshake message sizes.
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CVE-2026-55958 vulnerability anywhere in the article.