Buffer overflow in Op-Tee Optee OS
CVE-2026-71969
OP-TEE OS through 4.10.0, fixed in commit 7b8b494, contains a buffer underwrite vulnerability in the RSA NOPAD encrypt and decrypt operations within the mbedTLS software backend and SE050 hardware driver that allows a malicious Trusted Application to corrupt secure-world heap memory by supplying an input length exceeding the RSA modulus size. When src_len exceeds rsa_len, the subtraction expression wraps to a large unsigned value, causing a subsequent memcpy to write attacker-controlled data before the destination buffer in S-EL1 secure-world heap memory.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.7 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (6.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 6.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000
Affected products
- Op-Tee Optee OS — versions 0, 7b8b494e0a324cefec8ed386b7de413b44f1aaf3
Weakness classification (CWE)
References
- github.com/OP-TEE/optee_os/pull/7898 (issue-tracking)
- github.com/OP-TEE/optee_os/pull/7808 (issue-tracking)
- github.com/OP-TEE/optee_os/commit/7b8b494e0a324cefec8ed386b7de413b44f1aaf3 (patch)
- www.vulncheck.com/advisories/op-tee-os-buffer-underwrite-via-rsa-nopad-encrypt-… (third-party-advisory)
- blog.secmate.dev/posts/optee-vulnerabilities-disclosure/ (technical-description, exploit)
Frequently asked questions
- What is CVE-2026-71969?
- CVE-2026-71969 is a medium-severity vulnerability in Op-Tee Optee OS, classified under Buffer Underwrite. CVSS score: 6.7/10. Published 2026-08-10.
- How severe is CVE-2026-71969?
- Medium severity. CVSS v3 base score is 6.7 out of 10.