CVE-2026-31585

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

Weakness

The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/17cb7957c979529cc98ff57f7ac331532f1f7c83
• https://git.kernel.org/stable/c/25f19e476ab15defe698504212899fdb9f7cd61b
• https://git.kernel.org/stable/c/4bf95f797edd63c93330eafb6d6e670982344b9b
• https://git.kernel.org/stable/c/60f768d46df561e06d92ffcacc00909f37a0f23d
• https://git.kernel.org/stable/c/80900b5424f3454256153ce386388df43b324f63
• https://git.kernel.org/stable/c/83110c2c8c46c035c2e0fc8ff3e4991183bf9ccd
• https://git.kernel.org/stable/c/98c22210aeadce67d9d20059f0dbbd01ba7fdbba
• https://git.kernel.org/stable/c/a0e5a598fe9a4612b852406b51153b881592aede
• https://git.kernel.org/stable/c/f8cccb427e65d725fc0ba05e8900b4676eda268e