Description
VLC media player copies an RTSP response line into a fixed buffer without guaranteeing termination and then treats that buffer as a C string. RtspReadLine in modules/access/rtsp/access.c calls strncpy with the full buffer length, which writes no terminator when the source line is at least as long as the destination, and rtsp_get in modules/access/rtsp/rtsp.c allocates that buffer as BUF_SIZE bytes and passes it to strdup. When a server returns a line of 4096 bytes or more, strdup measures its length past the end of the allocation and copies adjacent heap bytes until an incidental zero byte. Because the affected line is the Session header, the disclosed bytes are retained as the session identifier and sent back to the server on every subsequent request, so the operator of a hostile server reads heap memory from the client rather than inferring it. The attacker controls the line length and therefore how far the read runs. A single playlist entry naming a realrtsp URL is sufficient. The module is a build-time option, disabled in some distribution packages and enabled in the official VideoLAN builds.
Published: 2026-09-09
Score: 6.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Wed, 09 Sep 2026 13:45:00 +0000

Type Values Removed Values Added
Description VLC media player copies an RTSP response line into a fixed buffer without guaranteeing termination and then treats that buffer as a C string. RtspReadLine in modules/access/rtsp/access.c calls strncpy with the full buffer length, which writes no terminator when the source line is at least as long as the destination, and rtsp_get in modules/access/rtsp/rtsp.c allocates that buffer as BUF_SIZE bytes and passes it to strdup. When a server returns a line of 4096 bytes or more, strdup measures its length past the end of the allocation and copies adjacent heap bytes until an incidental zero byte. Because the affected line is the Session header, the disclosed bytes are retained as the session identifier and sent back to the server on every subsequent request, so the operator of a hostile server reads heap memory from the client rather than inferring it. The attacker controls the line length and therefore how far the read runs. A single playlist entry naming a realrtsp URL is sufficient. The module is a build-time option, disabled in some distribution packages and enabled in the official VideoLAN builds.
Title VLC media player 3.0.0 through 3.0.23 Heap Out-of-Bounds Read via Unterminated RealRTSP Response Line
First Time appeared Videolan
Videolan vlc Media Player
Weaknesses CWE-125
CWE-170
CPEs cpe:2.3:a:videolan:vlc_media_player:*:*:*:*:*:*:*:*
Vendors & Products Videolan
Videolan vlc Media Player
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

Videolan Vlc Media Player
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-09T13:31:59.019Z

Reserved: 2026-08-11T21:47:14.059Z

Link: CVE-2026-73324

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-09T14:17:13.347

Modified: 2026-09-09T14:17:13.347

Link: CVE-2026-73324

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses