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NVD / CVE Program· CNA Linux

CVE-2026-90251: Bluetooth: MSFT: validate evt_prefix_len against the response length

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 0079e1a944634ab2dc1c7cdec1144486d096407e, 21f539c59ed330b671d75fd119c5f659ff92fbd1, 52b1b3b4d403cbda1b70ce2385e1a71f166a87ba; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 0079e1a944634ab2dc1c7cdec1144486d096407e, 21f539c59ed330b671d75fd119c5f659ff92fbd1, 52b1b3b4d403cbda1b70ce2385e1a71f166a87ba; 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: Bluetooth: MSFT: validate evt_prefix_len against the response length read_supported_features() only checks that the response covers the fixed part of struct msft_rp_read_supported_features, which is 11 bytes: if (skb->len < sizeof(*rp)) { bt_dev_err(hdev, "MSFT supported features length mismatch"); goto failed; } evt_prefix[] is a flexible array member and rp->evt_prefix_len is an unvalidated u8 taken straight out of that response, so msft->evt_prefix = kmemdup(rp->evt_prefix, rp->evt_prefix_len, GFP_KERNEL); copies up to 255 bytes from a reply that may have carried none of them. What is copied is data the controller never sent, and it is then used to match incoming vendor events in msft_vendor_evt(). This is not an out-of-bounds access. An skb data allocation always has at least SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) bytes past the payload, which is more than the 255 byte maximum, so the read stays inside the allocation and KASAN does not report it. It is still a read of bytes the host was never given, with the length fully controlled by the controller. Reject a response that is too short for the prefix it declares. Verified with an emulated controller over /dev/vhci on a KASAN kernel, with vhci made to advertise an MSFT opcode the way btintel, btqca, btmtk and btrtl do unconditionally. A reply of exactly 11 bytes declaring evt_prefix_len = 255 reaches kmemdup and copies 255 bytes ("skb->len=11 evt_prefix_len=255", with the copied buffer dumped); since the reply ends at the fixed part, all 255 come from past the end of the response. No KASAN report is produced, as expected from the allocation slack described above. With this patch the response is rejected with "MSFT event prefix length mismatch" and msft->evt_prefix is left unset.

—No exploit Fix available
Published
Sep 17, 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%

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Noroxi analysis

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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

    • 5.8affected
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before dce783a10e70f013410f5b583a29fc3286899629affected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 21f539c59ed330b671d75fd119c5f659ff92fbd1affected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 52b1b3b4d403cbda1b70ce2385e1a71f166a87baaffected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before e804d54a5a99d99250490e68093eff7190472e6faffected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 620c2631cff490d14d0b9d56f185cc745806d6d7affected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 7c2658023d839b651368a5b8b781bf9a817647cbaffected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 63562cfaea8a650fdb31ee8de21c32e3600be642affected · git
    • 145373cb1b1fcdba2059e945d0aa2613af2e84d1 and later · before 0079e1a944634ab2dc1c7cdec1144486d096407eaffected · git
    • before 5.8not 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-2026-90249Sep 17, 2026 · iio: light: gp2ap002: Fix unbalanced runtime PM on repeated event writes
    0Monitor
  • ← EarlierCVE-2026-90250Sep 17, 2026 · bpf, cgroup: Fix storage null-ptr-deref after replacing prog
    0Monitor
  • Later →CVE-2026-90252Sep 17, 2026 · Bluetooth: MGMT: free the HCI command when it is cancelled
    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 Linux0079e1a944634ab2dc1c7cdec1144486d096407eVendor (CNA)
Linux Linux21f539c59ed330b671d75fd119c5f659ff92fbd1Vendor (CNA)
Linux Linux52b1b3b4d403cbda1b70ce2385e1a71f166a87baVendor (CNA)
Linux Linux620c2631cff490d14d0b9d56f185cc745806d6d7Vendor (CNA)
Linux Linux63562cfaea8a650fdb31ee8de21c32e3600be642Vendor (CNA)
Linux Linux7c2658023d839b651368a5b8b781bf9a817647cbVendor (CNA)
Linux Linuxdce783a10e70f013410f5b583a29fc3286899629Vendor (CNA)
Linux Linuxe804d54a5a99d99250490e68093eff7190472e6fVendor (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).

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✗ → ✓

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References

Show all references (7 more)

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

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