CVE-2026-80545 s390/zcrypt: Improve EP11 CPRB length and overflow checks
An integer overflow in the s390/zcrypt driver allows buffer overflows, potentially enabling local attackers to execute code or escalate privileges.
- 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-2026-80545?
CVE-2026-80545 is a high-severity vulnerability in Linux, published on 26 Aug 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:
s390/zcrypt: Improve EP11 CPRB length and overflow checks
The xcrb_msg_to_type6_ep11cprb_msgx() function lacks proper input validation, creating security vulnerabilities: 1. Missing minimum size validation: The ep11_cprb structure and subsequent payload fields (pld_tag, pld_lenfmt) are copied from userspace without verifying sufficient buffer length. 2. Arithmetic overflow in length calculations: CEIL4 alignment could overflow, bypassing size checks and enabling buffer overflows. 3. The payload is asn1 encoded but the function just uses a simple c struct overlay to access some fields of the payload.
Fix by using size_t for length calculations, adding U32_MAX boundary checks after alignment, and validating minimum request size and minimum reply size before copying from userspace. Do a very simple asn1 parsing of the payload up to the function value field.
Which versions are affected by CVE-2026-80545?
How do I fix CVE-2026-80545?
Apply the vendor's patch.
Is CVE-2026-80545 being exploited?
There is no known exploitation of CVE-2026-80545 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-80545, GHSA-5h39-f843-4g5v, UBUNTU-CVE-2026-80545.