Bug 2461578 (CVE-2026-31585)

Summary: CVE-2026-31585 kernel: media: vidtv: fix nfeeds state corruption on start_streaming failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's vidtv media driver. When the `vidtv_start_streaming()` function fails, the internal counter for active streams (`nfeeds`) is not properly decremented. This state corruption can lead to memory leaks and prevent proper cleanup of resources, potentially causing system instability or a denial of service (DoS).
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Description OSIDB Bzimport 2026-04-24 15:09:28 UTC 
In the Linux kernel, the following vulnerability has been resolved:

media: vidtv: fix nfeeds state corruption on start_streaming failure

syzbot reported a memory leak in vidtv_psi_service_desc_init [1].

When vidtv_start_streaming() fails inside vidtv_start_feed(), the
nfeeds counter is left incremented even though no feed was actually
started. This corrupts the driver state: subsequent start_feed calls
see nfeeds > 1 and skip starting the mux, while stop_feed calls
eventually try to stop a non-existent stream.

This state corruption can also lead to memory leaks, since the mux
and channel resources may be partially allocated during a failed
start_streaming but never cleaned up, as the stop path finds
dvb->streaming == false and returns early.

Fix by decrementing nfeeds back when start_streaming fails, keeping
the counter in sync with the actual number of active feeds.

[1]
BUG: memory leak
unreferenced object 0xffff888145b50820 (size 32):
 comm "syz.0.17", pid 6068, jiffies 4294944486
 backtrace (crc 90a0c7d4):
  vidtv_psi_service_desc_init+0x74/0x1b0 drivers/media/test-drivers/vidtv/vidtv_psi.c:288
  vidtv_channel_s302m_init+0xb1/0x2a0 drivers/media/test-drivers/vidtv/vidtv_channel.c:83
  vidtv_channels_init+0x1b/0x40 drivers/media/test-drivers/vidtv/vidtv_channel.c:524
  vidtv_mux_init+0x516/0xbe0 drivers/media/test-drivers/vidtv/vidtv_mux.c:518
  vidtv_start_streaming drivers/media/test-drivers/vidtv/vidtv_bridge.c:194 [inline]
  vidtv_start_feed+0x33e/0x4d0 drivers/media/test-drivers/vidtv/vidtv_bridge.c:239
Comment 1 Keith Grant 2026-04-24 18:40:22 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042413-CVE-2026-31585-b423@gregkh/T