Stale nested SError syndrome via omitted ESR_EL2 write
Published Sep 4, 2026 · Updated Sep 4, 2026
Incorrect exception handling in Linux KVM arm64 allows guest OS users to observe stale ESR_EL2 after an injected nested SError. kvm_inject_el2_exception() constructs a syndrome but omits the ESR_EL2 write for SError, while enter_exception64() does not write ESR_ELx, so the value is dropped. The condition requires arm64 nested virtualization and an L2 hypervisor taking the injected SError; the bounded consequence is incorrect exception-state reporting inside that guest.
Summary
What happened
Incorrect exception handling in Linux KVM arm64 allows guest OS users to observe stale ESR_EL2 after an injected nested SError. kvm_inject_el2_exception() constructs a syndrome but omits the ESR_EL2 write for SError, while enter_exception64() does not write ESR_ELx, so the value is dropped. The condition requires arm64 nested virtualization and an L2 hypervisor taking the injected SError; the bounded consequence is incorrect exception-state reporting inside that guest.
The record
- CVE
- CVE-2026-80873
- Published
- Sep 4, 2026
- Updated
- Sep 4, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 4, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=6.17
- Affected versionversion=77ee70a073575977b403e9add25f185d614217d8 <09f35145f3a4aacea4d9b914ad895bf5af8fc4ae
- Affected versionversion=77ee70a073575977b403e9add25f185d614217d8 <29227821e2320ff6a174c91742b4ce221fe8d563
- Affected versionversion=77ee70a073575977b403e9add25f185d614217d8 <e2cb1f4578625e71f461d5c1ce70984193389cbb
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