CVE-2026-55958: Wolfssl · Out-of-bounds write in the Renesas TSIP TLS 1.3 transcript buffer
Affects wolfsslSource GCVE Database
Not known to be exploited · CVSS 7.5 High.
Data as of 30 Oct 2026, 06:59 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10wolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10wolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a patch is available, avoid using wolfSSL with the Renesas TSIP TLS port as a TLS 1.3 client on Renesas MCUs with TSIP hardware enabled, or apply any vendor-recommended workarounds if provided.
Description
An out-of-bounds write vulnerability exists in the Renesas TSIP TLS 1.3 transcript buffer within the tsip_StoreMessage() function of wolfSSL. The function does not return after detecting capacity overflow, causing a buffer overflow when processing large TLS 1.3 handshake messages. This can corrupt adjacent heap memory and potentially cause a remote denial of service. The issue affects only wolfSSL builds using the Renesas TSIP TLS port as a TLS 1.3 client on Renesas MCUs with TSIP hardware enabled. Other configurations are not affected.
References
- nvd.nist.gov/vuln/detail/CVE-2026-55958 (opens in a new tab)
- github.com/wolfSSL/wolfssl/pull/10705 (opens in a new tab)
- wolfssl.com/docs/security-vulnerabilities (opens in a new tab)
- ubuntu.com/security/CVE-2026-55958 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-55958 (opens in a new tab)
- wolfssl.com/docs/security-vulnerabilities/ (opens in a new tab)