CVE-2026-43823: Double Free (CVSS 7.5)

Description

When initializing an RSA public key from DER or PEM bytes throws an error, the EVP_PKEY* is double-freed: first in the catch block, then in the deinit. This can lead to a crash on future memory allocations. This double-free manifests when BoringSSL cannot decode the public key from the bytes provided. This vulnerability is addressed in swift-crypto version 4.5.1.

Is your site exposed to CVE-2026-43823?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

7.5

HIGH

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

EPSS — Exploit Prediction

0.0026

Probability of exploitation

0.17%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-415 CWE-415

References

Other References

https://github.com/apple/swift-crypto/security/advisories/GHSA-8q93-f6xh-4f6f https://github.com/apple/swift-crypto/security/advisories/GHSA-8q93-f6xh-4f6f

Frequently Asked Questions

What is CVE-2026-43823? +

When initializing an RSA public key from DER or PEM bytes throws an error, the EVP_PKEY* is double-freed: first in the catch block, then in the deinit. This can lead to a crash on future memory allocations. This double-free manifests when BoringSSL cannot decode the public key from the bytes provided. This vulnerability is addressed in swift-crypto version 4.5.1. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-43823? +

CVE-2026-43823 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0026, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-43823? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-12659

A denial-of-service security issue exists in the affected products. The security issue stems from improper handling of exceptional conditions when …

CVE-2025-2027

A double free vulnerability has been identified in the ASUS System Analysis service. This vulnerability can be triggered by sending …

CVE-2025-8058

The regcomp function in the GNU C library version from 2.4 to 2.41 is subject to a double free if …

CVE-2026-17573

A double free vulnerability was discovered in the HDF5 library. Processing a crafted HDF5 file containing an oversized chunk size …

CVE-2026-55995

A Double Free vulnerability in open-iscsi allows an unauthenticated MITM attacker to cause DoS. This issue affects open-iscsi: from ? …

CVE-2024-22097 9.8

A double-free vulnerability exists in the BrainVision Header Parsing functionality of The Biosig Project libbiosig Master Branch (ab0ee111) and 2.5.0. …

CVE-2026-43823