CVE-2025-39962 rxrpc: Fix untrusted unsigned subtract
An integer overflow in the Linux kernel's rxrpc module allows attackers to trigger memory corruption, potentially leading to code execution or system crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39962?
CVE-2025-39962 is a high-severity vulnerability in Linux kernel, published on 9 Oct 2025. 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:
rxrpc: Fix untrusted unsigned subtract
Fix the following Smatch static checker warning:
net/rxrpc/rxgk_app.c:65 rxgk_yfs_decode_ticket() warn: untrusted unsigned subtract. 'ticket_len - 10 * 4'
by prechecking the length of what we're trying to extract in two places in the token and decoding for a response packet.
Also use sizeof() on the struct we're extracting rather specifying the size numerically to be consistent with the other related statements.
Weakness: CWE-787
Which versions are affected by CVE-2025-39962?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-39962?
Apply the vendor's patch.
Is CVE-2025-39962 being exploited?
There is no known exploitation of CVE-2025-39962 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-39962, DEBIAN-CVE-2025-39962, GHSA-mhrx-xqmx-r77g, UBUNTU-CVE-2025-39962.