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Fencer Vulns
no cvss —

CVE-2023-53702 json

s390/crypto: use vector instructions only if available for ChaCha20

published 2025-10-22 12 mo ago modified 2026-10-28 11 d ago also EUVD-2023-60026

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

s390/crypto: use vector instructions only if available for ChaCha20

Commit 349d03ffd5f6 ("crypto: s390 - add crypto library interface for ChaCha20") added a library interface to the s390 specific ChaCha20 implementation. However no check was added to verify if the required facilities are installed before branching into the assembler code.

If compiled into the kernel, this will lead to the following crash, if vector instructions are not available:

data exception: 0007 ilc:3 [#1] SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc7+ #11 Hardware name: IBM 3931 A01 704 (KVM/Linux) Krnl PSW : 0704e00180000000 000000001857277a (chacha20_vx+0x32/0x818) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000037f0000000a ffffffffffffff60 000000008184b000 0000000019f5c8e6 0000000000000109 0000037fffb13c58 0000037fffb13c78 0000000019bb1780 0000037fffb13c58 0000000019f5c8e6 000000008184b000 0000000000000109 00000000802d8000 0000000000000109 0000000018571ebc 0000037fffb13718 Krnl Code: 000000001857276a: c07000b1f80b larl %r7,0000000019bb1780 0000000018572770: a708000a lhi %r0,10 #0000000018572774: e78950000c36 vlm %v24,%v25,0(%r5),0 >000000001857277a: e7a060000806 vl %v26,0(%r6),0 0000000018572780: e7bf70004c36 vlm %v27,%v31,0(%r7),4 0000000018572786: e70b00000456 vlr %v0,%v27 000000001857278c: e71800000456 vlr %v1,%v24 0000000018572792: e74b00000456 vlr %v4,%v27 Call Trace: [<000000001857277a>] chacha20_vx+0x32/0x818 Last Breaking-Event-Address: [<0000000018571eb6>] chacha20_crypt_s390.constprop.0+0x6e/0xd8 ---[ end trace 0000000000000000 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Fix this by adding a missing MACHINE_HAS_VX check.

[agordeev@linux.ibm.com: remove duplicates in commit message]

Patch / fix

  • Linux Linux 6.1.30, 6.3.4, 6.4
  • linux Debian 12 6.1.37-1
  • linux Debian 14, Debian 13 6.3.7-1

debian advisories DEBIAN-CVE-2023-53702

  • kernel RHEL 9 5.14.0-503.11.1.el9_5
  • rv RHEL 9 5.14.0-503.11.1.el9_5
  • perf RHEL 9 5.14.0-503.11.1.el9_5
  • rtla RHEL 9 5.14.0-503.11.1.el9_5
  • bpftool RHEL 9 7.4.0-503.11.1.el9_5
  • libperf RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-rt RHEL 9 5.14.0-503.11.1.el9_5
  • kernel-64k RHEL 9 5.14.0-503.11.1.el9_5

red hat advisories RHSA-2024:9315

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-53702 updated cvss 5.5

kernel: s390/crypto: use vector instructions only if available for ChaCha20

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available “Fix deferred”
  • Red Hat CodeReady Linux Builder (v. 9) libperf 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-s390x 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-x86_64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-aarch64 5.14.0-503.11.1.el9_5, kernel-debuginfo-common-ppc64le 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-503.11.1.el9_5, perf 5.14.0-503.11.1.el9_5, rtla 5.14.0-503.11.1.el9_5, kernel-devel-matched 5.14.0-503.11.1.el9_5, kernel-64k-devel-matched 5.14.0-503.11.1.el9_5, kernel-debug-devel-matched 5.14.0-503.11.1.el9_5, +6 more Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.4.0-503.11.1.el9_5, kernel 5.14.0-503.11.1.el9_5, kernel-64k 5.14.0-503.11.1.el9_5, kernel-core 5.14.0-503.11.1.el9_5, kernel-tools 5.14.0-503.11.1.el9_5, python3-perf 5.14.0-503.11.1.el9_5, +29 more Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, kernel-rt-modules-core 5.14.0-503.11.1.el9_5, kernel-rt-debug-modules 5.14.0-503.11.1.el9_5, +4 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-503.11.1.el9_5, kernel-rt-kvm 5.14.0-503.11.1.el9_5, kernel-rt-core 5.14.0-503.11.1.el9_5, kernel-rt-modules 5.14.0-503.11.1.el9_5, kernel-rt-debug-kvm 5.14.0-503.11.1.el9_5, kernel-rt-debug-core 5.14.0-503.11.1.el9_5, +6 more
    fixed: vendor fix RHSA-2024:9315
  • Red Hat CodeReady Linux Builder (v. 9) kernel-cross-headers 5.14.0-503.11.1.el9_5 Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 10 kernel Red Hat Enterprise Linux AppStream (v. 9) kernel-headers 5.14.0-503.11.1.el9_5
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.