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Asr1901 FirmwareOperating system · Asrmicro

CVE-2026-42800

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-30
Fix available
A fix is available. Upgrade to 1.225.003 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges 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
NULL pointer dereference vulnerability in ASR1903 in ASR Lapwing_Linux on Linux (ims_client modules) allows Pointer Manipulation. This vulnerability is associated with program files sip/utils/src/sipuri.c.

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

NULL pointer dereference vulnerability in the SIP URI parsing module (sip/utils/src/sipuri.c) within the ims_client modules on ASR1903 running ASR Lapwing_Linux allows pointer manipulation, potentially causing denial of service or undefined behavior via specially crafted SIP URIs.

MitigationApply vendor-supplied patch for CVE-2026-42800; if unavailable, implement NULL pointer validation checks in sipuri.c before dereferencing pointers in SIP URI handling functions to prevent the NULL dereference.

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
Asr1901 FirmwareOperating system
Affected:< 1.225.003
Asr1903 FirmwareOperating system
Affected:< 1.225.003

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

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

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. Identify the ASR device model
    Check the device model via CLI (show version, cat /proc/cpuinfo, or uci show system) or firmware banner during boot
    Affected if Device model is ASR1901 or ASR1903
  2. Determine the firmware version
    Run 'show version' or check /etc/version, /etc/os-release, or firmware info file depending on the device's CLI
    Affected if Firmware version is lower than 1.225.003 (e.g., 1.225.002, 1.224.x, etc.)
  3. Verify ims_client module presence
    Check for ims_client module via 'lsmod | grep ims' or examine loaded modules in /proc/modules, or look for ims_client in the firmware image
    Affected if ims_client modules are loaded or present on the system
  4. Confirm SIP URI parsing is in use
    Check for active SIP configuration or registrations via 'show sip status', examine config files in /etc/ims or /etc/sip directories, or monitor for SIP traffic on ports 5060/5061
    Affected if SIP functionality is enabled and the device processes SIP URIs

The device is affected if it is an ASR1901 or ASR1903 running firmware version below 1.225.003 with ims_client modules loaded and SIP URI parsing active.

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.

dbcve · scoped
Upgrade available Upgrade to 1.225.003 or later
Fixed in 1.225.003
Interim mitigation

Apply vendor-supplied patch for CVE-2026-42800; if unavailable, implement NULL pointer validation checks in sipuri.c before dereferencing pointers in SIP URI handling functions to prevent the NULL dereference.

Recommended fix High confidence

Firmware version 1.225.003 for Asr1901 and Asr1903

  1. 1. Identify the current firmware version of the affected Asr1901 or Asr1903 device
  2. 2. Download the fixed firmware version 1.225.003 from the official ASR Micro source (www.asrmicro.com)
  3. 3. Verify the integrity of the firmware file using checksums provided by the vendor
  4. 4. Back up the current device configuration
  5. 5. Upload and install firmware version 1.225.003 to the Asr1901 or Asr1903 device
  6. 6. Verify the upgrade was successful by confirming the new firmware version
  7. 7. Restart the device if required by the firmware update process
  8. 8. Test that the ims_client modules (sip/utils/src/sipuri.c) are functioning correctly
Caveat Review release notes for any configuration or feature changes between current version and 1.225.003; some settings may need adjustment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Asr1901 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2026-42800 in production — separate from our analysis above.

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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