CVE-2026-34871 json
Mbed TLS may use a low entropy PRNG seed
published 2026-04-01 7 mo ago modified 2026-07-18 3 mo ago also EUVD-2026-18001 , GHSA-rjq9-c3rf-c638 , JLSEC-2026-465
- cvss
- 6.7
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 9%
- public exploits
- 0
- none known
Summary
An issue was discovered in Mbed TLS before 3.6.6 and 4.x before 4.1.0 and TF-PSA-Crypto before 1.1.0. There is a Predictable Seed in a Pseudo-Random Number Generator (PRNG).
Patch / fix
- arm mbed_tls 3.6.6
- trustedfirmware tf-psa-crypto 1.1.0
- mbedtls Debian 14 3.6.6-0.1
debian advisories DEBIAN-CVE-2026-34871
- mbedtls openSUSE Tumbleweed 3.6.6-1.1
opensuse advisories openSUSE-SU-2026:10498-1
Vendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2026-34871 updated cvss 8.7
mbedtls: entropy on Linux can fall back to /dev/urandom
-
Red Hat All currently supported Red Hat productsnot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 6.7 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CNA | 3.1 | 6.7 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| OSV | 3.1 | 6.7 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | MbedTLS_jll | all versions |
no fix listed |
Classification
- Weakness
-
- CWE-338 Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
References
-
mbed-tls.readthedocs.io
/en/latest/security-advisories/
vendor-advisory, web
-
mbed-tls.readthedocs.io
/en/latest/security-advisories/mbedtls-security-advisory-2026-03-dev-random/
vendor-advisory, web
-
github.com
/advisories/GHSA-rjq9-c3rf-c638
web
-
mbed-tls.readthedocs.io
/en/latest/security-advisories
web
-
mbed-tls.readthedocs.io
/en/latest/security-advisories/mbedtls-security-advisory-2026-03-dev-random
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-34871
web
Sources
- CVE List CVE-2026-34871
- NVD CVE-2026-34871
- OSV JLSEC-2026-465
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.