# CVE-2022-49907: net: mdio: fix undefined behavior in bit shift for __mdiobus_register

Status: published. Published: 2025-05-01. Updated: 2026-11-05.

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

net: mdio: fix undefined behavior in bit shift for __mdiobus_register

Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned. The UBSAN warning calltrace like below:

UBSAN: shift-out-of-bounds in drivers/net/phy/mdio_bus.c:586:27
left shift of 1 by 31 places cannot be represented in type 'int'
Call Trace:
 <TASK>
 dump_stack_lvl+0x7d/0xa5
 dump_stack+0x15/0x1b
 ubsan_epilogue+0xe/0x4e
 __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
 __mdiobus_register+0x49d/0x4e0
 fixed_mdio_bus_init+0xd8/0x12d
 do_one_initcall+0x76/0x430
 kernel_init_freeable+0x3b3/0x422
 kernel_init+0x24/0x1e0
 ret_from_fork+0x1f/0x30
 </TASK>

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 20ed01a7b9af6e6a3c33761eebbb710ea6dd49b7 (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 7006176a3c863e3e353ce1b8a349ef5bb1b9320e (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < a3fafc974be37319679f36dc4e7cca7db1e02973 (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 4954b5359eb141499492fadfab891e28905509e2 (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 634f066d02bdb22a26da7deb0c7617ab1a65fc9d (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 985a88bf0b27193522bba7856b1763f428cef19d (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 6ce6f8f8f6316da6f92afe7490bc2f0b654d68e0 (affected, git); ≥ 4fd5f812c23c7deee6425f4a318e85c317cd1d6c; < 40e4eb324c59e11fcb927aa46742d28aba6ecb8a (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.28 (affected); ≥ 0; < 2.6.28 (unaffected, semver); ≥ 4.9.333; ≤ 4.9.* (unaffected, semver); ≥ 4.14.299; ≤ 4.14.* (unaffected, semver); ≥ 4.19.265; ≤ 4.19.* (unaffected, semver); ≥ 5.4.224; ≤ 5.4.* (unaffected, semver); ≥ 5.10.154; ≤ 5.10.* (unaffected, semver); ≥ 5.15.78; ≤ 5.15.* (unaffected, semver); ≥ 6.0.8; ≤ 6.0.* (unaffected, semver); ≥ 6.1; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.23% as of 2026-11-05; percentile 13.86%

- 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/20ed01a7b9af6e6a3c33761eebbb710ea6dd49b7 (CNA: Linux)

- https://git.kernel.org/stable/c/7006176a3c863e3e353ce1b8a349ef5bb1b9320e (CNA: Linux)

- https://git.kernel.org/stable/c/a3fafc974be37319679f36dc4e7cca7db1e02973 (CNA: Linux)

- https://git.kernel.org/stable/c/4954b5359eb141499492fadfab891e28905509e2 (CNA: Linux)

- https://git.kernel.org/stable/c/634f066d02bdb22a26da7deb0c7617ab1a65fc9d (CNA: Linux)

- https://git.kernel.org/stable/c/985a88bf0b27193522bba7856b1763f428cef19d (CNA: Linux)

- https://git.kernel.org/stable/c/6ce6f8f8f6316da6f92afe7490bc2f0b654d68e0 (CNA: Linux)

- https://git.kernel.org/stable/c/40e4eb324c59e11fcb927aa46742d28aba6ecb8a (CNA: Linux)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2022-49907; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2022-49907; retrieved 2026-11-05; source updated Not reported

Revision: 4ac7a2fb9a33c9a5789bf117f35dfb3ceec8cb9761c89404fc103223861a633b

Canonical: https://y2.dev/cve/CVE-2022-49907

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