CVE-2026-90327 phonet: pep: do not write beyond optlen in getsockopt
A local attacker can trigger a buffer overflow in the Linux kernel Phonet protocol via getsockopt, potentially leaking memory or causing a crash.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90327?
CVE-2026-90327 is a memory corruption vulnerability in Linux, published on 17 Sep 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:
phonet: pep: do not write beyond optlen in getsockopt
pep_getsockopt() clamps the reported length to the caller's buffer with min_t(), but then stores the value with put_user(val, (int __user *) optval), which always writes sizeof(int) bytes. A getsockopt() call with an optlen smaller than sizeof(int) thus reports the clamped length yet writes a full int, one to three bytes past the user buffer.
Write the value with copy_to_user() bounded by len, so at most optlen bytes are copied, matching the length reported back to userspace.
Which versions are affected by CVE-2026-90327?
How do I fix CVE-2026-90327?
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-2026-90327 being exploited?
There is no known exploitation of CVE-2026-90327 in the wild and no public exploit code.
Sources
Also known as AZL-102635, BELL-CVE-2026-90327, DEBIAN-CVE-2026-90327, GHSA-j842-pq84-9gpj, UBUNTU-CVE-2026-90327.