CVE-2023-21115

Paired-device privilege escalation via link-key downgrade

Published Jun 15, 2023 · Updated Dec 18, 2024

Cryptographic key downgrade in Android 11, 12, and 12L allows physically proximate attackers to escalate privileges over Bluetooth. The btm_sec_encrypt_change function in btm_sec.cc uses cryptography incorrectly, allowing the negotiated link-key type to be downgraded. Exploitation requires an already paired device, but requires neither additional execution privileges nor user interaction.

CVSS severity8.8
High
EPSS probability0.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic key downgrade in Android 11, 12, and 12L allows physically proximate attackers to escalate privileges over Bluetooth. The btm_sec_encrypt_change function in btm_sec.cc uses cryptography incorrectly, allowing the negotiated link-key type to be downgraded. Exploitation requires an already paired device, but requires neither additional execution privileges nor user interaction.

The record

CVE
CVE-2023-21115
Published
Jun 15, 2023
Updated
Dec 18, 2024
Vendor
Google Cloud
Product
Android
Classifications
CWE-327, T1404
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 15, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 18, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Android-11 Android-12 Android-12L

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Google Cloud · Androidversion=Android-11 Android-12 Android-12L

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1404Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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