Executive Summary

[{'type': 'paragraph', 'content': "This vulnerability is a 32-bit integer overflow in the wolfSSL library's function wolfssl_add_to_chain. It occurs when calculating the size of a new certificate chain using the sum of certain values, which can overflow and cause incorrect memory allocation."}, {'type': 'paragraph', 'content': 'Because of this overflow, heap corruption can happen when certificate data is written beyond the bounds of an insufficiently sized buffer.'}, {'type': 'paragraph', 'content': 'The affected function is called by several APIs related to adding certificate chains, which are enabled for third-party compatibility features.'}, {'type': 'paragraph', 'content': 'The issue is not remotely exploitable and requires that the application context loading certificates is already compromised.'}, {'type': 'paragraph', 'content': 'A fix was implemented by adding explicit bounds checking to prevent the overflow and ensure safe memory allocation.'}] [1]

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Impact Analysis

If exploited, this vulnerability can cause heap corruption due to writing certificate data out of bounds.

Heap corruption can lead to application instability, crashes, or potentially allow an attacker with local access to escalate privileges or execute arbitrary code.

However, this vulnerability is not remotely exploitable and requires that the application context loading certificates is already compromised, limiting the risk to local or pre-compromised environments.

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Compliance Impact

I don't know

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Detection Guidance

Detection of this vulnerability involves verifying whether the wolfSSL library in use contains the integer overflow issue in the function wolfssl_add_to_chain. Since the vulnerability is triggered by certificate chain length calculations leading to heap corruption, one practical approach is to run the regression test introduced in the wolfSSL API test suite that simulates certificate chain lengths approaching UINT32_MAX to check if the overflow condition is properly handled.

There are no specific network or system commands provided to detect exploitation attempts because the issue is not remotely exploitable and requires compromised application context loading certificates.

To detect if your wolfSSL version is vulnerable, you can check the version or patch level of the wolfSSL library installed. If you have access to the source or build environment, running the wolfSSL API test suite (tests/api.c) that includes the regression test for this overflow can help confirm if the fix is applied.

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Mitigation Strategies

The immediate mitigation step is to update the wolfSSL library to the version that includes the fix merged on February 25, 2026, which adds explicit bounds checking to prevent the integer overflow in wolfssl_add_to_chain.

Since the vulnerability is not remotely exploitable and requires compromised application context loading certificates, ensuring that your application environment is secure and that certificate loading processes are not exposed to untrusted inputs is also important.

Applying the patch or upgrading to a wolfSSL version containing the fix will prevent heap corruption caused by this integer overflow.

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