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CVE-2026-2411

Bluetooth GATT notify/indicate enforces the wrong attribute's permissions, bypassing encryption/authentication requirements on characteristic values

CVSS score

6.5

EPSS probability

%0.2

Risk score

0.0

Published

2 mo ago

Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-2411 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Characteristic Declaration whose permission is hard-coded to BT_GATT_PERM_READ, and a Characteristic Value attribute that carries the application-specified security permissions (e.g. BT_GATT_PERM_READ_ENCRYPT / READ_AUTHEN / READ_LESC). The public notify and indicate APIs explicitly accept either attribute, and passing the declaration is the documented, common idiom. Before sending each notification or indication, the host re-checks link security with bt_gatt_check_perm() against params->attr in gatt_notify(), gatt_indicate(), and gatt_notify_multiple_verify_params() (subsys/bluetooth/host/gatt.c). When the application passed the Characteristic Declaration attribute, the host correctly redirected the value handle but left params->attr pointing at the declaration, so the security check evaluated the declaration's permissions (no security required) instead of the value's. As a result the encryption/authentication/LESC requirement configured on the characteristic value was skipped. The Notify-Multiple path additionally used a mask that omitted the LE Secure Connections requirement. A remote peer triggers the disclosure by connecting (optionally without pairing or encryption) and writing the Client Characteristic Configuration descriptor to enable notifications or indications, causing the server to emit the protected value over a link that has not reached the required security level. The impact is information disclosure / access-control bypass for characteristic values the application intended to expose only over a secured link; exposure depends on the application declaring encrypt/authen-required notify/indicate characteristics and on the CCC being writable at a lower security tier. There is no memory-safety or availability impact. The fix adds bt_gatt_attr_resolve_value(), which maps a declaration attribute to the following value attribute before the permission check, and switches the Notify-Multiple path to the full BT_GATT_PERM_READ_ENCRYPT_MASK so the LESC requirement is also enforced.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-2411 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1zephyrprojectzephyr View
2zephyrprojectzephyr View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
6.5CVSS V3_1MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NCVE CNA
6.5CVSS V31MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

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cvelist

Fix commit

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
reference

Fix commit

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-2411 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-2411 weaknesses.

Attack Vector and Accessibility

ExposureBitişik ağ
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

6.5 / 10
Attack VectorAdjacentComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityNone

Vulnerability Scoring Details

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack VectorAdjacent network
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)None

Yama doğrulandı

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Weakness Type (CWE & CAPEC)

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