CVE-2023-21646Network attack vector

Cellular service interruption via invalid SIB1 assertion

Published Sep 5, 2023 · Updated Aug 2, 2024

Reachable assertion in Qualcomm modem firmware allows remote attackers to interrupt cellular service via an invalid System Information Block 1. The modem's SIB1 processing path accepts an invalid block far enough to reach an internal assertion instead of rejecting it safely. No authentication or user interaction is required; a successful trigger causes a transient modem service interruption without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Qualcomm modem firmware allows remote attackers to interrupt cellular service via an invalid System Information Block 1. The modem's SIB1 processing path accepts an invalid block far enough to reach an internal assertion instead of rejecting it safely. No authentication or user interaction is required; a successful trigger causes a transient modem service interruption without reported data disclosure or modification.

The record

CVE
CVE-2023-21646
Published
Sep 5, 2023
Updated
Aug 2, 2024
Vendor
Qualcomm
Product
Qualcomm SDX55M Firmware
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=*

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Qualcomm · Qualcomm SDX55M Firmwareversion=*
Qualcomm · Qualcomm SD780G Firmwareversion=*
Qualcomm · Qualcomm QCA6595AU Firmwareversion=*
Qualcomm · Qualcomm WCD9375 Firmwareversion=*
Qualcomm · Qualcomm Snapdragon 4 Gen 1 Firmwareversion=*
Qualcomm · SA515M Firmwareversion=*
Qualcomm · WSA8810 Firmwareversion=*
Qualcomm · QCA8337 Firmwareversion=*
Qualcomm · QCA8081 Firmwareversion=*
Qualcomm · WCD9360 Firmwareversion=*
Qualcomm · Qualcomm WCN6855 Firmwareversion=*
Qualcomm · QCM6490 Firmwareversion=*
Qualcomm · Qualcomm SM7325P Firmwareversion=*
Qualcomm · Snapdragonversion=AR8035; version=QCA6390; version=QCA6391; version=QCA6574A; version=QCA6595AU; version=QCA6696; version=QCA8081; version=QCA8337; version=QCM6490; version=QCN6024; version=QCN9024; version=QCS6490; version=QCX315; version=SA515M; version=SD480; version=SD690 5G; version=SD695; version=SD765; version=SD765G; version=SD768G; version=SD778G; version=SD780G; version=SD865 5G; version=SD870; version=SD888 5G; version=SD 8 Gen1 5G; version=SDX55; version=SDX55M; version=SDX65; version=SDX70M; version=SM7250P; version=SM7325P; version=Snapdragon 4 Gen 1; version=WCD9341; version=WCD9360; version=WCD9370; version=WCD9375; version=WCD9380; version=WCD9385; version=WCN3988; version=WCN3991; version=WCN3998; version=WCN6740; version=WCN6750; version=WCN6850; version=WCN6851; version=WCN6855; version=WCN6856; version=WCN7850; version=WCN7851; version=WSA8810; version=WSA8815; version=WSA8830; version=WSA8835
Qualcomm · Qualcomm WCN6856 Firmwareversion=*
Qualcomm · WCN7850 Firmwareversion=*
Qualcomm · Qualcomm SD768G Firmwareversion=*
Qualcomm · QCS6490 Firmwareversion=*
Qualcomm · WCN7851 Firmwareversion=*
Qualcomm · WCD9370 Firmwareversion=*
Qualcomm · Qualcomm SDX65 Firmwareversion=*
Qualcomm · SD 8 Gen1 5G Firmwareversion=*
Qualcomm · Qualcomm SM7250P Firmwareversion=*
Qualcomm · Qualcomm WCD9341 Firmwareversion=*
Qualcomm · WCN3988 Firmwareversion=*
Qualcomm · Qualcomm SD695 Firmwareversion=*
Qualcomm · Qualcomm SD888 5G Firmwareversion=*
Qualcomm · Qualcomm QCA6390 Firmwareversion=*
Qualcomm · Qualcomm SD765 Firmwareversion=*
Qualcomm · WCD9380 Firmwareversion=*
Qualcomm · Qualcomm WCN6740 Firmwareversion=*
Qualcomm · Qualcomm QCA6574A Firmwareversion=*
Qualcomm · Qualcomm WCN3991 Firmwareversion=*
Qualcomm · SD778G Firmwareversion=*
Qualcomm · QCN6024 Firmwareversion=*
Qualcomm · Qualcomm SD690 5G Firmwareversion=*
Qualcomm · Qualcomm SD870 Firmwareversion=*
Qualcomm · Qualcomm SD865 5G Firmwareversion=*
Qualcomm · AR8035 Firmwareversion=*
Qualcomm · QCN9024 Firmwareversion=*
Qualcomm · Qualcomm WCN6750 Firmwareversion=*
Qualcomm · Qualcomm SDX55 Firmwareversion=*
Qualcomm · Qualcomm WCN6851 Firmwareversion=*
Qualcomm · WSA8830 Firmwareversion=*
Qualcomm · QCA6391 Firmwareversion=*
Qualcomm · WCD9385 Firmwareversion=*
Qualcomm · Qualcomm WCN6850 Firmwareversion=*
Qualcomm · WSA8835 Firmwareversion=*
Qualcomm · Qualcomm WCN3998 Firmwareversion=*
Qualcomm · SD480 Firmwareversion=*
Qualcomm · Qualcomm SD765G Firmwareversion=*
Qualcomm · QCA6696 Firmwareversion=*
Qualcomm · WSA8815 Firmwareversion=*
Qualcomm · QCX315 Firmwareversion=*
Qualcomm · Qualcomm SDX70M Firmwareversion=*

Published CVSS scores

7.5Qualcomm, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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