CVE-2025-39928 (GCVE-0-2025-39928)

Vulnerability from cvelistv5 – Published: 2025-10-01 08:07 – Updated: 2026-01-14 17:42
VLAI?
Title
i2c: rtl9300: ensure data length is within supported range
Summary
In the Linux kernel, the following vulnerability has been resolved: i2c: rtl9300: ensure data length is within supported range Add an explicit check for the xfer length to 'rtl9300_i2c_config_xfer' to ensure the data length isn't within the supported range. In particular a data length of 0 is not supported by the hardware and causes unintended or destructive behaviour. This limitation becomes obvious when looking at the register documentation [1]. 4 bits are reserved for DATA_WIDTH and the value of these 4 bits is used as N + 1, allowing a data length range of 1 <= len <= 16. Affected by this is the SMBus Quick Operation which works with a data length of 0. Passing 0 as the length causes an underflow of the value due to: (len - 1) & 0xf and effectively specifying a transfer length of 16 via the registers. This causes a 16-byte write operation instead of a Quick Write. For example, on SFP modules without write-protected EEPROM this soft-bricks them by overwriting some initial bytes. For completeness, also add a quirk for the zero length. [1] https://svanheule.net/realtek/longan/register/i2c_mst1_ctrl2
Severity ?
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE
  • CWE-191 - Integer Underflow (Wrap or Wraparound)
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c366be720235301fdadf67e6f1ea6ff32669c074 , < c91382328fc89f73144d5582f2d8f1dd3e41c8f7 (git)
Affected: c366be720235301fdadf67e6f1ea6ff32669c074 , < 06418cb5a1a542a003fdb4ad8e76ea542d57cfba (git)
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    Linux Linux Affected: 6.13
Unaffected: 0 , < 6.13 (semver)
Unaffected: 6.16.8 , ≤ 6.16.* (semver)
Unaffected: 6.17 , ≤ * (original_commit_for_fix)
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Sightings

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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