CVE-2026-43495 net: wwan: t7xx: validate port_count against message length in t7xx_port_enum_msg_handler
A malicious modem can trigger a slab-out-of-bounds read in the Linux kernel t7xx WWAN driver, potentially causing a crash or leaking memory.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43495?
CVE-2026-43495 is a high-severity memory corruption vulnerability in Linux kernel, published on 21 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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: CWE-125
Which versions are affected by CVE-2026-43495?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43495?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-43495 being exploited?
There is no known exploitation of CVE-2026-43495 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43495, DEBIAN-CVE-2026-43495, GHSA-mhw6-p52x-6vxv, ROOT-OS-DEBIAN-12-CVE-2026-43495, ROOT-OS-UBUNTU-2404-CVE-2026-43495, UBUNTU-CVE-2026-43495.