CVE-2026-64546

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

drm/edid: fix OOB read in drm_parse_tiled_block()

drm_parse_tiled_block() casts the DisplayID block to a struct displayid_tiled_block and reads the full fixed layout up to tile->topology_id[7] without checking block->num_bytes. The DisplayID iterator only validates the declared payload length, so a crafted EDID can advertise a tiled-display block (tag DATA_BLOCK_TILED_DISPLAY, or DATA_BLOCK_2_TILED_DISPLAY_TOPOLOGY for v2.0) with a small num_bytes at the end of a DisplayID extension. The read then runs past the end of the exact-sized kmemdup()d EDID allocation, a heap out-of-bounds read.

Reject blocks shorter than the specs 22-byte tiled payload before reading the fixed struct, as drm_parse_vesa_mso_data() already does.

BUG: KASAN: slab-out-of-bounds in drm_edid_connector_update Read of size 2 at addr ffff888010077700 by task exploit/147 dump_stack_lvl (lib/dump_stack.c:94 …) print_report (mm/kasan/report.c:378 …) kasan_report (mm/kasan/report.c:595) drm_edid_connector_update (drivers/gpu/drm/drm_edid.c:7581) bochs_connector_helper_get_modes (drivers/gpu/drm/tiny/bochs.c:574) drm_helper_probe_single_connector_modes (drivers/gpu/drm/drm_probe_helper.c:426) status_store (drivers/gpu/drm/drm_sysfs.c:219) … vfs_write (fs/read_write.c:595 fs/read_write.c:688) ksys_write (fs/read_write.c:740)

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/157727131ce8a52d8d9bc676c372ef82db6436c4
• https://git.kernel.org/stable/c/4137e1ecec9c8cb6c4fcee28ffabbbc7409eb7fb
• https://git.kernel.org/stable/c/4f5484d25f85ad6c989bad5f6a43450cecfcfd28
• https://git.kernel.org/stable/c/9acd5c1ddc17ca4c5ffa0c373e3fdf480506e061
• https://git.kernel.org/stable/c/9cc0f8e63e8c34cf43def35cbd305ba711181a1f
• https://git.kernel.org/stable/c/bfa05d89dc3ca3fb1a9099ef5185549a5ec8490d
• https://git.kernel.org/stable/c/c4ab04ca1bbf87eefa9fec5c80e1880450d2e7c0
• https://git.kernel.org/stable/c/faaa1e1155833e7d4ce7e3cfaf64c0d636b190db