CVE-2021-25801
About
A buffer overflow vulnerability in the __Parse_indx component of VideoLAN VLC Media Player 3.0.11 allows attackers to cause an out-of-bounds read via a crafted .avi file.
Rainforest analyst review
A crafted .avi file drives VLC's __Parse_indx component into an out-of-bounds read, described as a buffer overflow. Exploitation needs a user to open the malicious file locally, and the impact is bounded, confidentiality and availability, with no integrity effect noted, so the realistic outcome is a crash or information leak.
This is client-side media handling: the delivery mechanism is convincing a user to open a booby-trapped video, which fits phishing or watering-hole delivery. It's weaponizable that way, but the user-interaction gate and the limited impact keep it out of remote, hands-off territory.
We handle this as endpoint software hygiene, inventorying where the affected VLC version is installed, and we flag plainly that it's file-triggered and interaction-dependent when ranking it. That keeps it prioritized as a user-targeted client bug rather than an exposed service vulnerability.
References
Related CVEs
Frequently asked questions
What is CVE-2021-25801?
A buffer overflow vulnerability in the __Parse_indx component of VideoLAN VLC Media Player 3.0.11 allows attackers to cause an out-of-bounds read via a crafted .avi file.
How severe is CVE-2021-25801?
CVE-2021-25801 carries a CVSS 3.1 base score of 7.1, rated high. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 62 out of 100, in the elevated band.
How is CVE-2021-25801 exploited?
According to the CVSS vector (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H): attack vector Local, attack complexity Low, privileges required None, user interaction Required. Impact on confidentiality High, integrity None and availability High.
Which products are affected by CVE-2021-25801?
Public advisories list the following as affected: vlc media player. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2021-25801?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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