7.1 High

The Object Transfer Service server builds its Object Action Control Point (OACP) response indication in oacpindsend()…

CVE-2026-81038

The Object Transfer Service server builds its Object Action Control Point (OACP) response indication in oacpindsend() (subsys/bluetooth/services/ots/otsoacp.c). Before this fix the four-byte Checksum Value field was appended whenever the requested op code was BTGATTOTSOACPPROCCHECKSUMCALC, regardless of the result code. The response payload is a bare, uninitialized four-byte stack buffer declared with NETBUFSIMPLEDEFINE(respparam, sizeof(uint32t)) in btgattotsoacpwrite(), and it is filled only on the success path of oacpchecksumprocvalidate(). On every failure path the buffer is still empty, so netbufsimplepullle32() was invoked on a zero-length buffer. The OACP characteristic and its client characteristic configuration descriptor are declared with BTGATTPERMWRITE and BTGATTPERMREAD | BTGATTPERMWRITE, so no pairing, encryption, or authentication is required. Any peer within radio range that can connect to a device running the OTS server can enable OACP indications and write a nine-byte Calculate Checksum command that fails validation — for example by issuing it with no object selected, which returns BTGATTOTSOACPRESINVOBJ. Because oacpcommanddecode() accepts the Calculate Checksum…

Assessment

CVSS: 7.1 (v3.1)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 26 October 2026
Last updated: 26 October 2026
Weakness: CWE-617, CWE-908
Assigner: vulnerabilities@zephyrproject.org

CVSS vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

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