CVE-2025-59729

Published Oct 6, 2025 Modified Apr 15, 2026 CWE-787

Description

When parsing the header for a DHAV file, there's an integer underflow in offset calculation that leads to reading the duration from before the start of the allocated buffer. If we load a DHAV file that is larger than MAX_DURATION_BUFFER_SIZE bytes (0x100000) for example 0x101000 bytes, then at [0] we have size = 0x101000. At [1] we have end_buffer_size = 0x100000, and at [2] we have end_buffer_pos = 0x1000. The loop then scans backwards through the buffer looking for the dhav tag; when it is found, we'll calculate end_pos based on a 32-bit offset read from the buffer. There is subsequently a check [3] that end_pos is within the section of the file that has been copied into end_buffer, but it only correctly handles the cases where end_pos is before the start of the file or after the section copied into end_buffer, and not the case where end_pos is within the the file, but before the section copied into end_buffer. If we provide such an offset, (end_pos - end_buffer_pos) can underflow, resulting in the subsequent access at [4] occurring before the beginning of the allocation. We recommend upgrading to version 8.0 or beyond.

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Weakness Type (CWE)

CWE-787 Out-of-bounds Write

References

Frequently Asked Questions

What is CVE-2025-59729? +
When parsing the header for a DHAV file, there's an integer underflow in offset calculation that leads to reading the duration from before the start of the allocated buffer. If we load a DHAV file that is larger than MAX_DURATION_BUFFER_SIZE bytes (0x100000) for example 0x101000 bytes, then at [0] we have size = 0x101000. At [1] we have end_buffer_size = 0x100000, and at [2] we have end_buffer_pos = 0x1000. The loop then scans backwards through the buffer looking for the dhav tag; when it is found, we'll calculate end_pos based on a 32-bit offset read from the buffer. There is subsequently a check [3] that end_pos is within the section of the file that has been copied into end_buffer, but it only correctly handles the cases where end_pos is before the start of the file or after the section copied into end_buffer, and not the case where end_pos is within the the file, but before the section copied into end_buffer. If we provide such an offset, (end_pos - end_buffer_pos) can underflow, resulting in the subsequent access at [4] occurring before the beginning of the allocation. We recommend upgrading to version 8.0 or beyond.
How do I check if I'm vulnerable to CVE-2025-59729? +
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.

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