CVE-2026-41676

rust-openssl: Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1

HIGH
7.5
CVSS Score
Published: April 24, 2026 at 05:16 PM UTC
Updated: July 15, 2026 at 04:34 PM UTC
2 products affected across 2 vendorsRust OpenSSLOpenSSL

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.9.27 ≤ v < 0.10.78
Affected range stops below 0.10.78, so it looks safe — our inference, not a vendor statement
v < 0.10.78
Affected range stops below 0.10.78, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

SSVC — Action Prioritization

SSVCNo known exploitAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787CWE-131

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