Bug 2535358 (CVE-2026-89880)

Summary: CVE-2026-89880 kernel: media: rtl2832_sdr: release URBs and stream buffers on start_streaming() failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the `rtl2832_sdr` media driver in the Linux kernel. Improper error handling during the `start_streaming()` function can lead to two latent defects. Specifically, if certain allocation or submission steps fail, previously allocated Universal Serial Bus (USB) Request Blocks (URBs) and stream buffers may not be properly released. This can result in a permanent memory leak and, upon subsequent streaming attempts, an out-of-bounds read when freeing URBs, potentially leading to memory corruption or a denial of service.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-16 12:19:38 UTC 
In the Linux kernel, the following vulnerability has been resolved:

media: rtl2832_sdr: release URBs and stream buffers on start_streaming() failure

rtl2832_sdr_start_streaming() calls rtl2832_sdr_alloc_stream_bufs(),
rtl2832_sdr_alloc_urbs() and rtl2832_sdr_submit_urbs() in sequence and
shares a single err: label that only unlocks the mutex and returns.
When alloc_urbs() succeeds but submit_urbs() fails, or when alloc_urbs()
itself returns -ENOMEM after alloc_stream_bufs() has already succeeded,
the URBs and/or the coherent DMA stream buffers stay allocated while
streaming reports failure to vb2. Two latent defects follow on the next
VIDIOC_STREAMON:

1) rtl2832_sdr_alloc_stream_bufs() unconditionally resets dev->buf_num
   to 0 and overwrites dev->buf_list[]/dev->dma_addr[], permanently
   leaking the coherent DMA memory allocated by the previous attempt.

2) rtl2832_sdr_alloc_urbs() never resets dev->urbs_initialized and only
   increments it. After a second successful pass urbs_initialized can
   exceed MAX_BULK_BUFS, so the subsequent rtl2832_sdr_free_urbs() walks
   from urbs_initialized - 1 down to 0 and reads past the end of
   dev->urb_list[], passing garbage pointers to usb_free_urb().

Mirror the teardown that stop_streaming() already performs: on the error
path call rtl2832_sdr_free_urbs() and rtl2832_sdr_free_stream_bufs()
before unlocking. Both helpers are idempotent (free_urbs kills and zeros
urbs_initialized; free_stream_bufs is gated on URB_BUF and clears the
buf_num counter), so partial-failure paths and the no-allocation paths
remain safe.

Issue identified by automated review of the INV-003 series at
https://sashiko.dev/
Comment 1 Mauro Matteo Cascella 2026-09-22 16:45:58 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89880.mbox