CVE-2026-89984: perf/x86/intel: Fix kernel address leakages in LBR stack
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 3c492c8eba02698ca893a9a13388d2adf6dfb839, 68c4b780b266a435261a1e029bede5ee3c2735cc, 6ac26161db27f7fb9d9e89ae240dbe52795496cc; 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 3c492c8eba02698ca893a9a13388d2adf6dfb839, 68c4b780b266a435261a1e029bede5ee3c2735cc, 6ac26161db27f7fb9d9e89ae240dbe52795496cc; 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: perf/x86/intel: Fix kernel address leakages in LBR stack Before Arch LBR gained CPL filtering support, a user-only branch stack could still contain kernel addresses. As a result, kernel branch records may be exposed to user space even when PERF_SAMPLE_BRANCH_USER is requested. For example, on Intel Tiger Lake, the following command can still report SYSRET/ERET entries with kernel-space from addresses: $ ./perf record -e cycles:p -o - --branch-filter any,save_type,u -- \ ./perf bench syscall basic --loop 1000 | \ ./perf script -i - --fields brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}' Total time: 0.000 [sec] 0.219000 usecs/op 4,566,210 ops/sec [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.551 MB - ] 0xffffffff93c001c8/0x7f12a2b1d647/P/-/-/16959/SYSRET/- 0xffffffff93c001c8/0x7f12a2b1d5c2/P/-/-/17535/SYSRET/- 0xffffffff93c01928/0x7f12a2861000/P/-/-/6719/ERET/- 0xffffffff93c01928/0x7f12a297a000/P/-/-/8575/ERET/- The problem is that intel_pmu_lbr_filter() does not fully validate the privilege level of sampled entries. It filters some mismatches based on the branch type and the to address, but it does not reject entries whose from address violates the requested branch privilege filter. Fix this by extending software filtering to validate both from and to addresses against br_sel. Any LBR entry contains kernel address does not match the requested user filter is dropped. This prevents kernel addresses from appearing in user-only branch stacks.
- Published
- Sep 16, 2026
- Updated
- Oct 19, 2026
- EPSS
- 0.2% · 11th percentile
- CWE
- —
Report tools
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
If any of these changes, we'll tell you in the daily email digest.
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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.
We use this product, ask for helpAffected 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
- 5.9affected
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before f3705db4e6378cc1b91a38ce0fe2f879055e23caaffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before b589147f54adc62e4172e4acf079ad5fb7b3687faffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before be0628a101ac05b085aaa4f650d48bd3915e80faaffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before ca19a175e89b7de604fab736436cbab74030b47aaffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before 6ac26161db27f7fb9d9e89ae240dbe52795496ccaffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before 3c492c8eba02698ca893a9a13388d2adf6dfb839affected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before 68c4b780b266a435261a1e029bede5ee3c2735ccaffected · git
- 47125db27e47e9d44c878bf8925aa057824bb0d5 and later · before e2b0575900ff72aa82748af96e7bd564ade5157aaffected · git
- before 5.9not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 6.1.190-1 | 6.1.190-1 |
| Debian:12 | linux-6.12 | before 6.12.111-1~deb12u1 | 6.12.111-1~deb12u1 |
| Debian:13 | linux | before 6.12.111-1 | 6.12.111-1 |
| Debian:14 | linux | before 7.2.6-1 | 7.2.6-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation40Plan
- CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment40Plan
- CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()40Plan
Published before and after this one in the same product
- ← EarlierCVE-2026-89982Sep 16, 2026 · i2c: mux: Fix channel node leak on adapter add failure0Monitor
- ← EarlierCVE-2026-89983Sep 16, 2026 · i2c: core: fix debugfs UAF on adapter removal0Monitor
- Later →CVE-2026-89985Sep 16, 2026 · memcg: keep folio's objcg same as its node31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 3c492c8eba02698ca893a9a13388d2adf6dfb839 | Vendor (CNA) |
| Linux Linux | 68c4b780b266a435261a1e029bede5ee3c2735cc | Vendor (CNA) |
| Linux Linux | 6ac26161db27f7fb9d9e89ae240dbe52795496cc | Vendor (CNA) |
| Linux Linux | b589147f54adc62e4172e4acf079ad5fb7b3687f | Vendor (CNA) |
| Linux Linux | be0628a101ac05b085aaa4f650d48bd3915e80fa | Vendor (CNA) |
| Linux Linux | ca19a175e89b7de604fab736436cbab74030b47a | Vendor (CNA) |
| Linux Linux | e2b0575900ff72aa82748af96e7bd564ade5157a | Vendor (CNA) |
| Linux Linux | f3705db4e6378cc1b91a38ce0fe2f879055e23ca | Vendor (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 3.0 | 6.6.157.1-1 · Release Notes | Microsoft (MSRC) |
| debian:linux | 6.1.190-1 · Debian:12 | Package registry (OSV) |
| debian:linux | 6.12.111-1 · Debian:13 | Package registry (OSV) |
| debian:linux-6.12 | 6.12.111-1~deb12u1 · Debian:12 | Package 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.
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 researchersFinders, 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.
- TR-26-1114 · Sep 17, 2026(Linux Kernel Güvenlik Bildirimi)
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
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (7 more)Show less
- git.kernel.org/stable/c/68c4b780b266a435261a1e029bede5ee3c2735cc
- git.kernel.org/stable/c/6ac26161db27f7fb9d9e89ae240dbe52795496cc
- git.kernel.org/stable/c/b589147f54adc62e4172e4acf079ad5fb7b3687f
- git.kernel.org/stable/c/be0628a101ac05b085aaa4f650d48bd3915e80fa
- git.kernel.org/stable/c/ca19a175e89b7de604fab736436cbab74030b47a
- git.kernel.org/stable/c/e2b0575900ff72aa82748af96e7bd564ade5157a
- git.kernel.org/stable/c/f3705db4e6378cc1b91a38ce0fe2f879055e23ca
Vendor advisories and official records. Exploit/PoC links are deliberately left out.