Bug 2524440 (CVE-2026-80545) - CVE-2026-80545 kernel: s390/zcrypt: Improve EP11 CPRB length and overflow checks
Summary: CVE-2026-80545 kernel: s390/zcrypt: Improve EP11 CPRB length and overflow checks
Keywords:
Status: NEW
Alias: CVE-2026-80545
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-26 14:53 UTC by OSIDB Bzimport
Modified: 2026-08-27 07:41 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-26 14:53:14 UTC
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.


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