High severity · published Apr 1, 2026
CVE-2026-34874
An issue was discovered in Mbed TLS through 3.6.5 and 4.x through 4.0.0
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
An issue was discovered in Mbed TLS through 3.6.5 and 4.x through 4.0.0. There is a NULL pointer dereference in distinguished name parsing that allows an attacker to write to address 0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 20% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MT
Mbed Tls · Trustedfirmware
3.5.0 before 3.6.6; 4.0.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34874
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34874
Vendor Advisory
https://mbed-tls.readthedocs.io/en/latest/security-advisories/
Vendor Advisory
https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-null-pointer-dereference-x509/
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