CVE-2026-31552 wifi: wlcore: Return -ENOMEM instead of -EAGAIN if there is not enough headroom
A logic error in the wlcore Wi-Fi driver causes an infinite loop and CPU soft lockup when memory allocation fails, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-31552?
CVE-2026-31552 is a high-severity denial of service vulnerability in Linux kernel, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: wlcore: Return -ENOMEM instead of -EAGAIN if there is not enough headroom
Since upstream commit e75665dd0968 ("wifi: wlcore: ensure skb headroom before skb_push"), wl1271_tx_allocate() and with it wl1271_prepare_tx_frame() returns -EAGAIN if pskb_expand_head() fails. However, in wlcore_tx_work_locked(), a return value of -EAGAIN from wl1271_prepare_tx_frame() is interpreted as the aggregation buffer being full. This causes the code to flush the buffer, put the skb back at the head of the queue, and immediately retry the same skb in a tight while loop.
Because wlcore_tx_work_locked() holds wl->mutex, and the retry happens immediately with GFP_ATOMIC, this will result in an infinite loop and a CPU soft lockup. Return -ENOMEM instead so the packet is dropped and the loop terminates.
The problem was found by an experimental code review agent based on gemini-3.1-pro while reviewing backports into v6.18.y.
Weakness: CWE-835
Which versions are affected by CVE-2026-31552?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-31552?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-31552 being exploited?
There is no known exploitation of CVE-2026-31552 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-31552, DEBIAN-CVE-2026-31552, GHSA-f5xv-cjm8-337g, ROOT-OS-DEBIAN-11-CVE-2026-31552, ROOT-OS-DEBIAN-12-CVE-2026-31552, ROOT-OS-DEBIAN-13-CVE-2026-31552 and 3 more.