# CVE-2025-38229: media: cxusb: no longer judge rbuf when the write fails

Status: published. Published: 2025-07-04. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

media: cxusb: no longer judge rbuf when the write fails

syzbot reported a uninit-value in cxusb_i2c_xfer. [1]

Only when the write operation of usb_bulk_msg() in dvb_usb_generic_rw()
succeeds and rlen is greater than 0, the read operation of usb_bulk_msg()
will be executed to read rlen bytes of data from the dvb device into the
rbuf.

In this case, although rlen is 1, the write operation failed which resulted
in the dvb read operation not being executed, and ultimately variable i was
not initialized.

[1]
BUG: KMSAN: uninit-value in cxusb_gpio_tuner drivers/media/usb/dvb-usb/cxusb.c:124 [inline]
BUG: KMSAN: uninit-value in cxusb_i2c_xfer+0x153a/0x1a60 drivers/media/usb/dvb-usb/cxusb.c:196
 cxusb_gpio_tuner drivers/media/usb/dvb-usb/cxusb.c:124 [inline]
 cxusb_i2c_xfer+0x153a/0x1a60 drivers/media/usb/dvb-usb/cxusb.c:196
 __i2c_transfer+0xe25/0x3150 drivers/i2c/i2c-core-base.c:-1
 i2c_transfer+0x317/0x4a0 drivers/i2c/i2c-core-base.c:2315
 i2c_transfer_buffer_flags+0x125/0x1e0 drivers/i2c/i2c-core-base.c:2343
 i2c_master_send include/linux/i2c.h:109 [inline]
 i2cdev_write+0x210/0x280 drivers/i2c/i2c-dev.c:183
 do_loop_readv_writev fs/read_write.c:848 [inline]
 vfs_writev+0x963/0x14e0 fs/read_write.c:1057
 do_writev+0x247/0x5c0 fs/read_write.c:1101
 __do_sys_writev fs/read_write.c:1169 [inline]
 __se_sys_writev fs/read_write.c:1166 [inline]
 __x64_sys_writev+0x98/0xe0 fs/read_write.c:1166
 x64_sys_call+0x2229/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 77829a5f5a74026b888b0529628475b29750cef4 (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 390b864e3281802109dfe56e508396683e125653 (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 41807a5f67420464ac8ee7741504f6b5decb3b7c (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 84eca597baa346f09b30accdaeca10ced3eeba2d (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 04354c529c8246a38ae28f713fd6bfdc028113bc (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 9bff888c92f5c25effbb876d22a793c2388c1ccc (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 8b35b50b7e98d8e9a0a27257c8424448afae10de (affected, git); ≥ 22c6d93a73105fddd58796d7cb10f5f90ee2a338; < 73fb3b92da84637e3817580fa205d48065924e15 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.13 (affected); ≥ 0; < 2.6.13 (unaffected, semver); ≥ 5.4.296; ≤ 5.4.* (unaffected, semver); ≥ 5.10.239; ≤ 5.10.* (unaffected, semver); ≥ 5.15.186; ≤ 5.15.* (unaffected, semver); ≥ 6.1.142; ≤ 6.1.* (unaffected, semver); ≥ 6.6.95; ≤ 6.6.* (unaffected, semver); ≥ 6.12.35; ≤ 6.12.* (unaffected, semver); ≥ 6.15.4; ≤ 6.15.* (unaffected, semver); ≥ 6.16; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-05; percentile 7.96%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/77829a5f5a74026b888b0529628475b29750cef4 (CNA: Linux)

- https://git.kernel.org/stable/c/390b864e3281802109dfe56e508396683e125653 (CNA: Linux)

- https://git.kernel.org/stable/c/41807a5f67420464ac8ee7741504f6b5decb3b7c (CNA: Linux)

- https://git.kernel.org/stable/c/84eca597baa346f09b30accdaeca10ced3eeba2d (CNA: Linux)

- https://git.kernel.org/stable/c/04354c529c8246a38ae28f713fd6bfdc028113bc (CNA: Linux)

- https://git.kernel.org/stable/c/9bff888c92f5c25effbb876d22a793c2388c1ccc (CNA: Linux)

- https://git.kernel.org/stable/c/8b35b50b7e98d8e9a0a27257c8424448afae10de (CNA: Linux)

- https://git.kernel.org/stable/c/73fb3b92da84637e3817580fa205d48065924e15 (CNA: Linux)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html (ADP: CVE)

- https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html (ADP: CVE)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2025-38229; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-38229; retrieved 2026-11-05; source updated Not reported

Revision: e79e02a6bde761b7111a19d8f0a89ec511e2a497c1873414b0e67d23d03808bb

Canonical: https://y2.dev/cve/CVE-2025-38229

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