CVE-2026-55958 Affecting wolfssl package, versions <5.9.2-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-WOLFSSL-17547609
- published26 Jun 2026
- disclosed25 Jun 2026
Introduced: 25 Jun 2026
CVE-2026-55958 (opens in a new tab)How to fix?
Upgrade Debian:unstable wolfssl to version 5.9.2-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream wolfssl package and not the wolfssl package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.