CVE-2026-25833: Mbed TLS · Stack-based Buffer Overflow
Source CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in 3.6.6 : patch affected systems soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 23% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.6.6
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 1 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
AI-suggested
Upgrade Mbed TLS to version 3.6.6 or later, or 4.1.0 or later, where the buffer overflow in x509_inet_pton_ipv6() is fixed. Patch status is confirmed by the vendor's versioning information. No other mitigations are indicated.
Description
A buffer overflow vulnerability exists in the x509_inet_pton_ipv6() function of Mbed TLS versions 3.5.0 through 3.6.5. This issue was fixed in versions 3.6.6 and 4.1.0.