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AndroidOperating system · Google

CVE-2023-21073

MEDIUM · 6.7 CVSS v3.1 Published 2023-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In rtt_unpack_xtlv_cbfn of dhd_rtt.c, there is a possible out of bounds write due to a buffer overflow. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-257290396References: N/A

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A buffer overflow vulnerability exists in the rtt_unpack_xtlv_cbfn function within dhd_rtt.c in the Android kernel. The function fails to properly validate bounds when unpacking XTLV (eXtensible Type-Length-Value) data, leading to an out-of-bounds write. This allows a local attacker with System execution privileges to escalate to higher privileges.

MitigationApply the Android kernel security patch for A-257290396, which addresses the boundary check deficiency in the RTT driver. This is typically delivered through monthly Android security update bundles.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AndroidOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify the RTT (802.11mc Fine Timing Measurement) feature is enabled
    Check if Wi-Fi RTT is enabled on the device by inspecting the kernel configuration or runtime status: look for 'CONFIG_WLAN_FEATURE_RTT' in /boot/config* or check if 'rtt' appears in /sys/module/wlan/parameters/ (on affected Broadcom/Cypress Wi-Fi chipsets using the dhd driver)
    Affected if RTT support is compiled into the kernel or loaded as a module (dhd.ko) and the feature is active - this is required for the vulnerable code path to be reachable
  2. Confirm the Android kernel version
    Run 'uname -r' or check /proc/version to obtain the kernel version string
    Affected if The kernel version predates the Android security patch for CVE-2023-21073 (A-257290396) - typically versions before the monthly security update that includes this fix
  3. Inspect the dhd_rtt.c source or binary for the vulnerability
    Check the dhd_rtt.ko module (typically found in /lib/modules/*/kernel/drivers/net/wireless/bcmdhd/ or /vendor/lib/modules/) for the rtt_unpack_xtlv_cbfn function - look for XTLV unpacking logic without proper boundary checks; alternatively, verify if the vendor shipped a kernel that includes the patched code
    Affected if The compiled dhd driver module lacks the boundary check fix in the XTLV unpacking routine (missing validation before write operations in rtt_unpack_xtlv_cbfn)
  4. Verify the security patch level
    Check the Android security patch level via 'getprop ro.build.version.security_patch' or Settings > About Phone > Android security patch level
    Affected if The security patch level is earlier than the monthly update that contains the fix for A-257290396

A device is affected if it runs any unpatched Android version with the RTT (Wi-Fi Fine Timing Measurement) feature enabled and uses a Broadcom/Cypress dhd driver containing the vulnerable rtt_unpack_xtlv_cbfn function.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Android kernel security patch for A-257290396, which addresses the boundary check deficiency in the RTT driver. This is typically delivered through monthly Android security update bundles.

Fix this in Android Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-21073 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data