Buffer overflow in Rust-Openssl
CVE-2026-41676
rust-openssl provides OpenSSL bindings for the Rust programming language. From 0.9.27 to before 0.10.78, Deriver::derive (and PkeyCtxRef::derive) sets len = buf.len() and passes it as the in/out length to EVP_PKEY_derive, relying on OpenSSL to honor it. On OpenSSL 1.1.x, X25519, X448, DH and HKDF-extract ignore the incoming *keylen, unconditionally writing the full shared secret (32/56/prime-size bytes). A caller passing a short slice gets a heap/stack overflow from safe code. OpenSSL 3.x providers do check, so this only impacts older OpenSSL. This vulnerability is fixed in 0.10.78.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.003 (18.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 18.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Rust-Openssl — versions >= 0.9.27, < 0.10.78
- Rust-Openssl Project
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-41676?
- CVE-2026-41676 is a high-severity vulnerability in Rust-Openssl, classified under Incorrect Calculation of Buffer Size. CVSS score: 7.5/10. Published 2026-04-24.
- How severe is CVE-2026-41676?
- High severity. CVSS v3 base score is 7.5 out of 10.