CVE-2021-25480
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 · uneditedA lack of replay attack protection in GUTI REALLOCATION COMMAND message process in Qualcomm modem prior to SMR Oct-2021 Release 1 can lead to remote denial of service on mobile network connection.
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 · high confidenceA replay attack vulnerability exists in the GUTI REALLOCATION COMMAND message handling of Qualcomm modem firmware prior to SMR Oct-2021 Release 1. An attacker can capture and retransmit valid GUTI reallocation messages, causing the mobile device to accept stale or invalid identifiers, which disrupts the mobile network connection and results in denial of service.
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= 8.0= 8.1= 9.0= 10.0= 11.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Check Android OS versionGo to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADBAffected if Android version is 8.0, 8.1, 9.0, 10.0, or 11.0
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Identify modem chipset vendorCheck device specifications for Qualcomm Snapdragon chipset, or run 'getprop ro.bootloader' or 'getprop ro.ril.gprsclass' via ADB to confirm Qualcomm basebandAffected if Device uses Qualcomm modem firmware (this vulnerability affects only Qualcomm modem firmware, not other modem vendors)
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Check Qualcomm modem firmware versionRun 'getprop persist.radio.baseband' or 'getprop gsm.version.baseband' via ADB, or check in Settings > About Phone > SIM Status > Carrier menuAffected if Modem firmware version cannot be determined or is earlier than the SMR Oct-2021 Release 1 patch level
User is affected if device runs Android 8.0-11.0 with Qualcomm modem firmware prior to the SMR Oct-2021 Release 1 patch, as the missing replay protection in GUTI REALLOCATION COMMAND handling allows network disruption.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scopedUpdate Qualcomm modem firmware to SMR Oct-2021 Release 1 or later, which includes proper replay attack protection mechanisms for GUTI REALLOCATION COMMAND messages.
SMR Oct-2021 Release 1 or later (Security Maintenance Release)
- Verify current Android version by going to Settings > About Phone > Android version
- Check for system updates by going to Settings > System > Software Update or Settings > Software Update
- Download and install the SMR (Security Maintenance Release) October 2021 or later update
- After update completes, verify the patch date reflects October 2021 or later in Settings > About Phone > Software information > Security patch level
- If OTA update is not available, contact device manufacturer or carrier for the specific firmware update containing the Qualcomm modem security fix
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,352.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-25480 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-25480 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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