What’s Vulnerable › Vulnerabilities

CVE-2026-80921: KVM: s390: vsie: zero stale crypto bits

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-09 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: vsie: zero stale crypto bits When shadowing crypto access bits from a format0 apcb (crycb 0 or 1), the bits 64..255 are unchanged from whatever is in the vsie page in the crycb and thus in the apcb. This gives a nested guest potential access to a device no longer available. Zero out the remaining bits.

Affected products

• Linux kernel: 4.20 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/087c19cc60a8caa1a08e1e434c8be2caf6c27733
• https://git.kernel.org/stable/c/29b4f7bc2991313bd3e6f6fb8fdf1b173f086dd6
• https://git.kernel.org/stable/c/34d5b5b646c91cfb9338d7a12c955a70ffb8c66b
• https://git.kernel.org/stable/c/59d51550b5cb916bda037673a721a404b3b47a0d
• https://git.kernel.org/stable/c/7d23489f51109e3ebba5b5db8c5f0185af7b7fdf
• https://git.kernel.org/stable/c/935eeba276012916c76243e5cbb843efd8fdb75d
• https://git.kernel.org/stable/c/d110b3297f11ef227098b8a82ade2d5f123b7d2f
• https://git.kernel.org/stable/c/d4bcd2df6d0d2af916b4fe1a533958778ea7c45b
• https://git.kernel.org/stable/c/f6079dca67eccb5eabef9f72437948c66dc5131f

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