CVE-2025-38027

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

regulator: max20086: fix invalid memory access

max20086_parse_regulators_dt() calls of_regulator_match() using an array of struct of_regulator_match allocated on the stack for the matches argument.

of_regulator_match() calls devm_of_regulator_put_matches(), which calls devres_alloc() to allocate a struct devm_of_regulator_matches which will be de-allocated using devm_of_regulator_put_matches().

struct devm_of_regulator_matches is populated with the stack allocated matches array.

If the device fails to probe, devm_of_regulator_put_matches() will be called and will try to call of_node_put() on that stack pointer, generating the following dmesg entries:

max20086 6-0028: Failed to read DEVICE_ID reg: -121 kobject: xc0$xa5x03 (000000002cebcb7a): is not initialized, yet kobject_put() is being called.

Followed by a stack trace matching the call flow described above.

Switch to allocating the matches array using devm_kcalloc() to avoid accessing the stack pointer long after its out of scope.

This also has the advantage of allowing multiple max20086 to probe without overriding the data stored inside the global of_regulator_match.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/5578ab04bd7732f470fc614bbc0a924900399fb8
• https://git.kernel.org/stable/c/6b0cd72757c69bc2d45da42b41023e288d02e772
• https://git.kernel.org/stable/c/6ba30f7aa2c550b2ac04f16b81a19a8c045b8660
• https://git.kernel.org/stable/c/7bddac8603d4e396872c2fbf4403ec08e7b1d7c8
• https://git.kernel.org/stable/c/d2a9a92bb4cc7568cff68241b0051dc7268bdc68
• https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html