CVE-2025-66442 json
Mbed TLS timing side channel in RSA and CBC/ECB decryption
published 7mo ago modified 5d ago also EUVD-2025-209171 , JLSEC-2026-463
- cvss
- 5.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 20%
- public exploits
- 0
- none known
Summary
In Mbed TLS through 4.0.0, there is a compiler-induced timing side channel (in RSA and CBC/ECB decryption) that only occurs with LLVM's select-optimize feature. TF-PSA-Crypto through 1.0.0 is also affected.
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Check with FencerVendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2025-66442 updated cvss 5.9
mbedtls: Mbed TLS and TF-PSA-Crypto: Information disclosure via compiler-induced timing side channel
-
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
- 7mo ago
Exploit prediction
0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 5.1 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| CNA | 3.1 | 5.1 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| OSV | 3.1 | 5.1 | CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| julia | MbedTLS_jll | all versions |
no fix listed |
Classification
- Weakness
-
- CWE-385 Covert Timing Channel
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-compiler-induced-constant-time-violations/
vendor-advisory, web
-
github.com
/Mbed-TLS/mbedtls/releases
release-notes, web
-
github.com
/Mbed-TLS/TF-PSA-Crypto/releases
release-notes, web
Sources
- CVE List CVE-2025-66442
- NVD CVE-2025-66442
- OSV JLSEC-2026-463
Fencer Intel 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.