KVM: s390: Free guest debug data on vcpu destroy
In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Free guest debug data on vcpu destroy kvm_s390_clear_bp_data() is only called from kvm_arch_vcpu_ioctl_set_guest_debug(), i.e. when user space changes or disables debugging. A vCPU that is destroyed while hardware breakpoints are still armed - the normal case when the VMM just exits or crashes - leaks hw_bp_info, hw_wp_info and all old_data buffers, since generic KVM frees the vCPU right after kvm_arch_vcpu_destroy(). That is bounded by MAX_BP_COUNT entries, so roughly 8 KiB per vCPU, but it is unbounded over VM lifetimes. The allocations are GFP_KERNEL_ACCOUNT, so the charge also outlives the exiting process and pins dying memcgs. Fix by clearing the debug data on vCPU destruction. Calling it unconditionally is fine: struct kvm_vcpu is zero allocated, so for a vCPU that never enabled debugging the counters are 0 and the pointers NULL.
CVE-2026-89923
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-89923
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "053f2068cf9b0654b651fed5ad7649d3deb982bf",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "6c996b12bbe4a6023076e8eee3cfaf2cc99db76c",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "d6280fc540d8f4653c9b54a78cb747e128070f5e",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "544a5a665019cef394ce8bda97fa7a2cab253781",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "9a32c4c6a6c23b7f5bf765eb5b83ba7f64a8ec63",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "b5acacfdb8966abff91836c1c5bd7da59d8a526e",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "e4d8b7f176b976474e0800ba71ee2dfa3ce263c9",
"versionType": "git"
},
{
"status": "affected",
"version": "27291e2165b6de70c476b7b675308113edd69a60",
"lessThan": "e7f698b09d4a7c36b299acf680fc50fe868e2bcd",
"versionType": "git"
}
],
"programFiles": [
"arch/s390/kvm/kvm-s390.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.16"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.16",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/s390/kvm/kvm-s390.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89923
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36366 · Revision 1
- Added to Heist Feed
- Publisher date