Back to CVE records
Medium 5.1Published Apr 1, 2026
CVE-2025-66442In 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.
Updated under an hour ago ()
Does this affect you?
It affects arm mbed_tls and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Start free and add your stack
Free account, 1 product
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.
- CVSS
- 5.1 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-385
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
arm mbed_tls arm:mbed_tls | through 4.0.0 | NVD |
arm tf-psa-crypto arm:tf-psa-crypto | through 1.0.0 | NVD |
References
- https://github.com/Mbed-TLS/TF-PSA-Crypto/releasesrelease-notes
- https://github.com/Mbed-TLS/mbedtls/releasesrelease-notes
- 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-compiler-induced-constant-time-violations/vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.