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NVD / CVE Program· CNA Linux

CVE-2026-89924: KVM: s390: Fix old_data leak in guest debug error path

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 124c81ee610e1fbdd93d4399f88d9e28ba97a941, 4048d0a252163084794be3e37995b872c5178913, 46cb8a273e2f853f89a78b59dbdff8787b6e1c86; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 124c81ee610e1fbdd93d4399f88d9e28ba97a941, 4048d0a252163084794be3e37995b872c5178913, 46cb8a273e2f853f89a78b59dbdff8787b6e1c86; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: KVM: s390: Fix old_data leak in guest debug error path __import_wp_info() allocates a per-watchpoint old_data buffer to back up the original guest memory contents. If a later watchpoint of the same KVM_SET_GUEST_DEBUG request fails to import, kvm_s390_import_bp_data() jumps to the error label, which frees the wp_info array but not the old_data buffers of the entries that were imported successfully. Up to MAX_BP_COUNT - 1 buffers of up to MAX_WP_SIZE bytes are leaked per failed request, and the request can be repeated. Create error handling for cleaning up all created old_data memory areas.

—No exploit Fix available
Published
Sep 16, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.16affected
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before 124c81ee610e1fbdd93d4399f88d9e28ba97a941affected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before e5ae7816e5ad145618f7fd568a0e8a94dd9f81f4affected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before c85d402553987777cc4742751437ea5dcbf98a7baffected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before 5fbf319137735252eefa507193c9a619af5b7457affected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before 4048d0a252163084794be3e37995b872c5178913affected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before f55e4d415d95342d5753e528e05a1e8623992c3faffected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before 46cb8a273e2f853f89a78b59dbdff8787b6e1c86affected · git
    • 27291e2165b6de70c476b7b675308113edd69a60 and later · before aa9c8e8baf1e765fa65b93212522c636f25d846faffected · git
    • before 3.16not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-89922Sep 16, 2026 · KVM: s390: Take srcu when importing watchpoint data
    31Monitor
  • ← EarlierCVE-2026-89923Sep 16, 2026 · KVM: s390: Free guest debug data on vcpu destroy
    0Monitor
  • Later →CVE-2026-89925Sep 16, 2026 · KVM: s390: Fix memory leak in guest debug handling
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux124c81ee610e1fbdd93d4399f88d9e28ba97a941Vendor (CNA)
Linux Linux4048d0a252163084794be3e37995b872c5178913Vendor (CNA)
Linux Linux46cb8a273e2f853f89a78b59dbdff8787b6e1c86Vendor (CNA)
Linux Linux5fbf319137735252eefa507193c9a619af5b7457Vendor (CNA)
Linux Linuxaa9c8e8baf1e765fa65b93212522c636f25d846fVendor (CNA)
Linux Linuxc85d402553987777cc4742751437ea5dcbf98a7bVendor (CNA)
Linux Linuxe5ae7816e5ad145618f7fd568a0e8a94dd9f81f4Vendor (CNA)
Linux Linuxf55e4d415d95342d5753e528e05a1e8623992c3fVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records