CVE-2026-43495

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

net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler

t7xx_port_enum_msg_handler() uses the modem-supplied port_count field as a loop bound over port_msg->data[] without checking that the message buffer contains sufficient data. A modem sending port_count=65535 in a 12-byte buffer triggers a slab-out-of-bounds read of up to 262140 bytes.

Add a sizeof(*port_msg) check before accessing the port message header fields to guard against undersized messages.

Add a struct_size() check after extracting port_count and before the loop.

In t7xx_parse_host_rt_data(), guard the rt_feature header read with a remaining-buffer check before accessing data_len, validate feat_data_len against the actual remaining buffer to prevent OOB reads and signed integer overflow on offset.

Pass msg_len from both call sites: skb->len at the DPMAIF path after skb_pull(), and the validated feat_data_len at the handshake path.

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/0e7c074cfcd9bd93765505f9eb8b42f03ed2a744
• https://git.kernel.org/stable/c/2b56d7903ab804481f5233a259d5f341e9fd513c
• https://git.kernel.org/stable/c/307c5d0f36a5c74042217136da5bfbd9f7504650
• https://git.kernel.org/stable/c/9855e063e063158cc5bded576382599dc3133202
• https://git.kernel.org/stable/c/dd4f4c93c1488d7100b9964f2da4c8b3c29652f1
• https://git.kernel.org/stable/c/f94450ce5053b36002995b72d1fa1db3bb08c5bf
• http://www.openwall.com/lists/oss-security/2026/06/18/1