CVE-2026-98348 Overview
CVE-2026-98348 is an out-of-bounds read vulnerability in the Linux kernel's libipw wireless support library. The flaw resides in libipw_handle_assoc_resp(), which processes IEEE 802.11 association response frames for the legacy ipw2100 and ipw2200 Intel wireless drivers. A size arithmetic error allows an attacker on an adjacent wireless network to send a truncated association response frame that triggers a read far beyond the receive buffer. The vulnerability was resolved upstream by rejecting association response frames shorter than the 30-byte fixed prefix before any field is parsed.
Critical Impact
An adjacent attacker can send a malformed 802.11 association response to crash the kernel or disclose adjacent memory on systems using the ipw2100 or ipw2200 wireless drivers.
Affected Products
- Linux kernel wireless subsystem (libipw)
- Intel ipw2100 wireless driver
- Intel ipw2200 wireless driver
Discovery Timeline
- 2026-10-06 - CVE-2026-98348 published to NVD
- 2026-10-07 - Last updated in NVD database
Technical Details for CVE-2026-98348
Vulnerability Analysis
The vulnerability is a numeric truncation and out-of-bounds read in libipw_handle_assoc_resp(). The function expects a 30-byte association response prefix containing the capability, status, and association ID (AID) fields. It then computes the length of the trailing information elements as stats->len - sizeof(*frame).
stats->len is a u16, while sizeof() returns a size_t. The subtraction promotes to size_t, so when stats->len is smaller than the fixed frame size the result wraps to a very large unsigned value instead of becoming negative. That value is then truncated to the u16 length parameter of libipw_parse_info_param(), producing a length close to 64 KiB.
The parser proceeds to walk information elements well past the end of the receive buffer, leading to kernel memory disclosure or a crash. The ipw2100 and ipw2200 receive paths only validate the generic 24-byte three-address header before dispatching to this function, so the oversized read is reachable without any further sanity checks.
Root Cause
The root cause is unchecked length arithmetic between differently sized unsigned integer types. The code assumes stats->len is always at least sizeof(*frame) and performs no explicit guard, allowing a short frame to wrap the computation. This fits the pattern of a Numeric Truncation Error combined with an Out-of-Bounds Read in a kernel driver.
Attack Vector
Exploitation requires wireless proximity: the attacker must transmit a crafted management frame that reaches a victim running a vulnerable ipw2100 or ipw2200 driver. The frame must present a valid 24-byte three-address 802.11 header while declaring a total length shorter than the 30-byte association response fixed prefix.
No authentication to the target wireless network is required, as management frames are processed before association completes. The resulting read of up to ~64 KiB past the buffer can cause kernel panics or leak adjacent kernel memory into subsequent processing, depending on allocation layout.
Detection Methods for CVE-2026-98348
Indicators of Compromise
- Kernel Oops, BUG, or KASAN splats originating in libipw_handle_assoc_resp or libipw_parse_info_param.
- Unexpected ipw2100 or ipw2200 driver resets, disconnects, or wireless interface crashes.
- Dmesg entries referencing out-of-bounds reads in the libipw module shortly after association attempts.
Detection Strategies
- Monitor kernel ring buffer (dmesg) and /var/log/kern.log for faults within the libipw, ipw2100, or ipw2200 modules.
- Enable KASAN on test hosts to flag out-of-bounds reads during 802.11 fuzzing of management frames.
- Audit endpoint inventories for systems still shipping or using Intel PRO/Wireless 2100 and 2200BG hardware with vulnerable kernels.
Monitoring Recommendations
- Collect kernel crash telemetry centrally and alert on repeated crashes correlated with wireless activity.
- Track kernel package versions against the fixed commits listed in the kernel.org stable tree to confirm patch coverage.
- Watch for anomalous 802.11 management frame volumes near corporate wireless perimeters where legacy adapters remain in use.
How to Mitigate CVE-2026-98348
Immediate Actions Required
- Apply the latest stable Linux kernel update from your distribution that includes the libipw length-validation fix.
- Where patching is delayed, unload the ipw2100 and ipw2200 modules and blacklist them until the kernel is updated.
- Replace end-of-life Intel PRO/Wireless 2100 and 2200BG adapters with supported hardware on exposed hosts.
Patch Information
The upstream fix rejects association response frames shorter than the fixed-field prefix before any field is dereferenced. The change was backported across multiple stable branches. Reference commits: 14cb425ba1f3, 400b89217058, 46aa75291056, 766268b429ae, adb7118b7d2c, af1b69be19c3, d70bdb84cf17, and e3025ecdb205.
Workarounds
- Blacklist the vulnerable drivers by adding blacklist ipw2100 and blacklist ipw2200 under /etc/modprobe.d/ and rebuilding initramfs.
- Physically disable or remove affected wireless adapters on systems that cannot be patched promptly.
- Restrict mobility of vulnerable hosts to trusted wireless environments to reduce exposure to adjacent-network attackers.
# Prevent the vulnerable modules from loading until the kernel is patched
echo 'blacklist ipw2100' | sudo tee /etc/modprobe.d/cve-2026-98348.conf
echo 'blacklist ipw2200' | sudo tee -a /etc/modprobe.d/cve-2026-98348.conf
sudo rmmod ipw2200 2>/dev/null
sudo rmmod ipw2100 2>/dev/null
sudo update-initramfs -u
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.