CVE-2026-68255

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

drm/virtio: bound EDID block reads to the response buffer

virtio_get_edid_block() validates the read offset only against the device-supplied resp->size field, never against the fixed-size resp->edid array. The EDID block index is driven by the device-supplied extension count, so a malicious virtio-gpu backend can advertise a large size together with a high block count and read far past the array into adjacent kernel memory, which is then surfaced in the parsed EDID (an out-of-bounds read / info leak).

Also reject any read whose end exceeds the size of the edid array. Conforming EDID responses stay within the array and are unaffected.

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/2757e6e803092cf0aeaf4b735e16b5d3bdc705c5
• https://git.kernel.org/stable/c/35be0e2c6862abcd5e5f5445261f1fd910d4a9b4
• https://git.kernel.org/stable/c/375c1934ef0196d3b6d3a1eae3232bef8dae7bf7
• https://git.kernel.org/stable/c/3f506a85a905b080cadc029a1651a310479090a6
• https://git.kernel.org/stable/c/4e1a53892ba7f8a3e1da6bfc53c83ae7c812dccd
• https://git.kernel.org/stable/c/64bedd2758eccbc74d39f7006a7ec16fa39dc901
• https://git.kernel.org/stable/c/65ce911f341ad8ff0c08922eff5bb6db75666eb0
• https://git.kernel.org/stable/c/9fc2a017c5d597937e0c28b9a9669844aa796c42