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.
This page covers CVE-2026-55958 as tracked by Debian, for the package wolfssl. No fixed version has been recorded for this distribution yet.
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.
The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
DEBIAN-CVE-2026-55958 is classified as CWE-393: Return of Wrong Status Code. A function or operation returns an incorrect return value or status code that does not indicate the true result of execution, causing the product to modify its behavior based on the incorrect result.
DEBIAN-CVE-2026-55958 is recorded against 1 package.
Published on 25 June 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.
security-tracker.debian.org (Advisory)
wolfssl has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-393: Return of Wrong Status Code) in other software:
Details
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| wolfssl | — | — |
References
Similar Threats
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