CVE-2026-41676: rust-openssl Deriver::derive And PkeyCtxRef::derive Can Overflow Vulnerability

HIGH
Advisory Identifier: GHSA-pqf5-4pqq-29f5
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CWE-787 CWE-131
Published
Advisory Summary

CVE-2026-41676 is a HIGH deriver::derive and pkeyctxref::derive can overflow vulnerability (CWE-787: Out-of-bounds Write) affecting rust-openssl libraries in the crates.io ecosystem. The issue involves deriver::derive and pkeyctxref::derive can overflow short buffers on openssl 1.1.1. Remediation is available by upgrading affected packages to version 0.10.78.

CVE-2026-41676 at a Glance

CVE Identifier CVE-2026-41676
GHSA Identifier GHSA-pqf5-4pqq-29f5
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-787: Out-of-bounds Write
Affected Product rust-openssl
Package Ecosystem crates.io
Published Date
Last Updated

How to Fix CVE-2026-41676

To remediate this vulnerability, upgrade all affected rust-openssl dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

openssl fixed: 0.10.78 
Upgrade openssl to 0.10.78
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for openssl

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-41676, inspect your project dependencies for rust-openssl:

inspect dependencies for openssl

Analyze the terminal output to locate any version of rust-openssl in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.10.78), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-787: Out-of-bounds Write, where the product writes data past the end, or before the beginning, of the intended buffer. In rust-openssl, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

`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.

CVE-2026-41676 Affected rust-openssl Versions

1 component(s)
Fixed Versions:
0.10.78
Product / Package Ecosystem Affected Versions Fixed Version
openssl
 crates.io
≥ 0.9.27
< 0.10.78
0.10.78

References

GitHub Advisory / Wiki ADVISORY
https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-pqf5-4pqq-29f5
NVD — CVE-2026-41676 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-41676
rust-openssl Source Repository REPOSITORY
https://github.com/rust-openssl/rust-openssl/pull/2606
Security Fix Commit FIX COMMIT
https://github.com/rust-openssl/rust-openssl/commit/09b425e5f59a2466d806e71a83a9a449c914c596
rust-openssl Source Repository REPOSITORY
https://github.com/rust-openssl/rust-openssl
rust-openssl Release RELEASE
https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78

Frequently Asked Questions

What is CVE-2026-41676?
CVE-2026-41676 is a security vulnerability in rust-openssl involving Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1 under CWE-787: Out-of-bounds Write.
Which rust-openssl versions are affected?
Affected versions include releases prior to 0.10.78 across affected packages: openssl.
What version fixes CVE-2026-41676?
Upgrading to 0.10.78 (or the latest patched release for your respective branch) resolves the vulnerability.
Is openssl affected?
Yes, openssl is affected in releases prior to 0.10.78. Upgrade your dependency to 0.10.78 or later.
What CWE is associated with CVE-2026-41676?
CVE-2026-41676 is classified under CWE-787: Out-of-bounds Write (The product writes data past the end, or before the beginning, of the intended buffer.).
How can I check crates.io dependencies for CVE-2026-41676?
Run the dependency tree command: 'inspect dependencies for openssl'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-pqf5-4pqq-29f5",
  "modified" : "2026-04-27T16:42:03Z",
  "published" : "2026-04-22T21:22:00Z",
  "aliases" : [ "CVE-2026-41676" ],
  "summary" : "rust-openssl: Deriver::derive and PkeyCtxRef::derive can overflow short buffers on OpenSSL 1.1.1",
  "details" : "`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.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "openssl"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.9.27"
      }, {
        "fixed" : "0.10.78"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-pqf5-4pqq-29f5"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41676"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/pull/2606"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/commit/09b425e5f59a2466d806e71a83a9a449c914c596"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rust-openssl/rust-openssl"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rust-openssl/rust-openssl/releases/tag/openssl-v0.10.78"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-131", "CWE-787" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-22T21:22:00Z",
    "nvd_published_at" : "2026-04-24T18:16:29Z"
  }
}