CVE-2026-41676 — Vulnerability in openssl — CVE Details

HIGH

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

Published April 22, 2026Updated September 10, 2026Source: osv

Summary

`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.

Advisory Timeline

First published April 22, 2026 (173 days ago).
Last revised September 10, 2026 — 140 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Cargo

Update openssl to 0.10.78 or later

cargo update -p openssl --precise 0.10.78

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Affects 1 ecosystem: crates.io (1).

Package	Ecosystem	Affected	Fixed In
openssl	crates.io	All versions	0.10.78

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CWE-131
View on MITRE
CWE-787
Out-of-bounds WriteMITRE

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 9.3 score means for each attack dimension.

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

—

Confidentiality

—

Integrity

—

Availability

—

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U

References

Frequently Asked Questions

What is CVE-2026-41676?: rust-openssl: Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1 This vulnerability has been assigned a severity rating of HIGH (CVSS score: 9.3/10).
How do I check if my project is affected by CVE-2026-41676?: CVE-2026-41676 affects openssl. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-41676 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score

9.3

Exploitation is straightforward and causes maximum impact. Patch immediately.

Also Known As

GHSA-pqf5-4pqq-29f5

Related CVEs

CVE-2018-20997
CRITICAL
Use after free in openssl
CVE-2016-10931
HIGH
SSL/TLS MitM vulnerability due to insecure defaults
CVE-2016-10931
HIGH
Improper Certificate Validation in openssl
CVE-2026-41678
HIGH
rust-openssl has incorrect bounds assertion in aes key wrap
CVE-2026-41681
HIGH
rust-openssl: rustMdCtxRef::digest_final() writes past caller buffer with no length check
CVE-2026-41898
HIGH
rust-openssl: Unchecked callback length in PSK/cookie trampolines leaks adjacent memory to peer
CVE-2026-42327
HIGH
rust-openssl has undefined behavior in X509Ref::ocsp_responders for certificates with non-UTF-8 OCSP URLs
CVE-2026-41677
LOW
rust-opennssl has an Out-of-bounds read in PEM password callback when returning an oversized length

Check if you're affected

Scan your dependencies to see if this vulnerability affects your projects.

Scan Your Dependencies