Skip to content
Fencer Vulns
high 7.5

CVE-2021-45451 json

In Mbed TLS before 3.1.0, `psa_aead_generate_nonce` allows policy bypass or oracle-based decryption...

published 2021-12-21 4 y ago modified 2026-07-23 3 mo ago also EUVD-2021-32222 , JLSEC-2025-216

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

In Mbed TLS before 3.1.0, psa_aead_generate_nonce allows policy bypass or oracle-based decryption when the output buffer is at memory locations accessible to an untrusted application.

Patch / fix

  • julia MbedTLS_jll 2.28.0+0
  • arm mbed_tls 3.1.0

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-2021-45451 updated cvss 7.5

mbedtls: policy bypass/oracle-based decryption in psa_aead_generate_nonce

  • Red Hat All currently supported Red Hat products
    not 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 ICSA-24-046-11 updated cvss 7.5

Siemens SCALANCE XCM-/XRM-300

  • Siemens SCALANCE XCH328 (6GK5328-4TS01-2EC2) <V2.4 Siemens SCALANCE XCM324 (6GK5324-8TS01-2AC2) <V2.4 Siemens SCALANCE XCM328 (6GK5328-4TS01-2AC2) <V2.4 Siemens SCALANCE XCM332 (6GK5332-0GA01-2AC2) <V2.4 Siemens SCALANCE XRH334 (24 V DC, 8xFO, CC) (6GK5334-2TS01-2ER3) <V2.4 Siemens SCALANCE XRM334 (2x230 V AC, 8xFO) (6GK5334-2TS01-4AR3) <V2.4
    +5 more products
    Siemens SCALANCE XRM334 (2x230 V AC, 12xFO) (6GK5334-3TS01-4AR3) <V2.4 Siemens SCALANCE XRM334 (24 V DC, 8xFO) (6GK5334-2TS01-2AR3) <V2.4 Siemens SCALANCE XRM334 (24 V DC, 12xFO) (6GK5334-3TS01-2AR3) <V2.4 Siemens SCALANCE XRM334 (230 V AC, 8xFO) (6GK5334-2TS01-3AR3) <V2.4 Siemens SCALANCE XRM334 (230 V AC, 12xFO) (6GK5334-3TS01-3AR3) <V2.4
    affected: fixed in V2.4 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia MbedTLS_jll
<2.28.0+0
2.28.0+0

Classification

Weakness
  • CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

Sources

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.