VLC Media Player Hit by Two Memory Corruption Flaws Exploitable via Malicious PNG and Rogue RealRTSP Server

Two vulnerabilities have been discovered in the VLC media player that allow out-of-bounds memory access. The issues affect versions from 3.0.0 through 3.0.23. CVE-2026-56711, rated 8.6 on CVSS 4.0, stems from an integer overflow when calculating image buffer sizes in PNG files, enabling attackers to trigger writes beyond allocated memory simply by opening a crafted image or loading it from a playlist. CVE-2026-73324, scored 6.9, resides in the RealRTSP module and permits a malicious server to send an oversized response string that causes reads past the end of a buffer due to a missing null terminator. Both flaws are present in official VideoLAN builds, although some distributions may exclude the RealRTSP component. No special configuration or plugins are required to trigger the issues. Until patched releases appear, users are advised to avoid opening images or playlists from untrusted sources and to refrain from connecting to unknown RealRTSP streams.

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VLC media player contains two memory corruption vulnerabilities that can be triggered without any special configuration or plugins.

The more severe flaw, CVE-2026-56711, received an 8.6 CVSS 4.0 score. It is caused by an integer overflow during buffer-size calculation for PNG images. An attacker can supply an image with abnormally large width and height values, forcing VLC to allocate an undersized memory region and then write data beyond its boundaries. The vulnerability activates when a malicious PNG is opened directly or referenced inside a playlist.

The second issue, CVE-2026-73324, carries a 6.9 CVSS score and affects the RealRTSP module. A malicious server can return a response string longer than 4096 bytes that lacks a terminating null character. As a result, VLC continues reading memory past the intended buffer, potentially disclosing adjacent data to the attacker-controlled server.

Both vulnerabilities impact official VideoLAN builds of VLC versions 3.0.0 through 3.0.23. Some Linux distributions may ship the player without the RealRTSP module enabled. Until patched versions are released, users should refrain from opening images or playlists from untrusted sources and avoid connecting to unknown RealRTSP streams.

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