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VulnerabilityPublished Updated

CVE-2026-55958: Wolfssl · Out-of-bounds write in the Renesas TSIP TLS 1.3 transcript buffer

Affects wolfsslSource GCVE Database

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Not known to be exploited · CVSS 7.5 High.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Ubuntu 26.10wolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=stonkingOther threatsAffected
  • =5.9.1-0.1
  • =5.9.2-1
Fixed in–
Ubuntu 26.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=resoluteOther threatsAffected
  • 5.7.2-0.1 – 5.9.1-0.1
4 affected builds
Fixed in–
Ubuntu 25.10wolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=questingOther threatsAffected
  • =5.7.2-0.1
Fixed in–
Ubuntu 24.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=nobleOther threatsAffected
  • 5.5.4-2 – 5.6.6-1.3build1
6 affected builds
Fixed in–
Ubuntu 22.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=jammyOther threatsAffected
  • 4.6.0-3 – 5.2.0-2
5 affected builds
Fixed in–
Ubuntu 20.04 LTSwolfsslpkg:deb/ubuntu/wolfssl?arch=source&distro=focalOther threatsAffected
  • 4.1.0+dfsg-2 – 4.3.0+dfsg-2
5 affected builds
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

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