CVE-2026-80708

What the bug is

The helper function _ip_cprb_helper() uses internal buffer memory for building and processing CPRBs. After use this buffer was never scrubbed which could lead to leaving for example clear key material in memory which could be exposed via tricky reuse of this same memory. Extend the _ip_cprb_helper() function with another parameter 'scrub' used to steer scrubbing of this buffer. So now the caller has the opportunity to decide if scrubbing is needed or not. Extend the clear key to secure key token import process in function cca_clr2cipherkey() to tell the helper function from above to scrub the cprb buffer when the clear key value is part of the request data. Add explicit scrubbing on return from function cca_clr2cipherkey() for the random EXOR buffer and the cprb buffer. Overall this cleans the internal used buffer in case of clear key import to prevent sensitive data to get exposed.

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/s390/crypto/zcrypt_ccamisc.c

What this is

S390 ZCRYPT AND PKEY DRIVER AND AP BUSMAINTAINERS section matched on drivers/s390/crypto/ · linux-s390@vger.kernel.org · Supported

Kernel module

zcrypt

Check it on the machine

grep -wE 'CONFIG_S390|CONFIG_ZCRYPT' /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w zcrypt

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian does not build this code in 2 releases. It does build it in 3 releases, so the answer depends on which release the machine runs.

• bookwormn
• trixieMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt/amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64
• forky, sidMnot built on amd64/amd64, amd64/cloud-amd64, amd64/rt-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64
• bookworm · linux-6.12n

n

not enabled on any flavour - this release does not build the code

M

a module where it is built at all; some flavours do not build it

Build switches

CONFIG_S390, CONFIG_ZCRYPT

Reads as

all on means the file is compiled; any one off means it is not.

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-08-28 (2 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.22%, higher than 11.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/s390

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
5.4	5.10.265	8e1c0def77b7
5.4	5.15.216	be7ae07fb745
5.4	6.1.183	4e26d0d72bfd
5.4	6.6.152	7dd6e556dbfc
5.4	6.12.104	b453003ae6a8
5.4	6.18.44	fbb0410986e8
5.4	7.1.8	ebfbb9ac7adb
5.4	7.2	01476391aece

Debian advisories