Exynos W920 FirmwareOperating system · Samsung

CVE-2025-26781

HIGH · 7.5 CVSS v3.1 Published 2025-10-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
An issue was discovered in L2 in Samsung Mobile Processor, Wearable Processor, and Modem Exynos 980, 990, 850, 1080, 2100, 1280, 2200, 1330, 1380, 1480, 9110, W920, W930, Modem 5123, and Modem 5300. Incorrect handling of RLC AM PDUs leads to a Denial of Service.

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 confidence

A vulnerability in the L2 (Layer 2) processing of Samsung Exynos mobile processors, wearable processors, and cellular modems allows incorrect handling of RLC AM (Radio Link Control Acknowledged Mode) Protocol Data Units, leading to a Denial of Service condition. The issue affects multiple Exynos chip generations used in mobile devices and wearables.

MitigationApply vendor-provided firmware/security updates from Samsung for affected devices. Since this is a hardware-level firmware issue in cellular modems, no configuration workarounds are available.

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
Exynos W920 FirmwareOperating system
Affected:all versions
Exynos 1080 FirmwareOperating system
Affected:all versions
Exynos 980 FirmwareOperating system
Affected:all versions
Exynos 990 FirmwareOperating system
Affected:all versions
Exynos 850 FirmwareOperating system
Affected:all versions
Exynos 2200 FirmwareOperating system
Affected:all versions
Exynos 1330 FirmwareOperating system
Affected:all versions
Exynos 1380 FirmwareOperating 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
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 checks

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

  1. Identify the Exynos chipset model in the device
    Check the device specifications, system information, or modem firmware details to confirm the Exynos chip model (e.g., W920, 1080, 980, 990, 850, 2200, 1330, or 1380)
    Affected if The device uses any of the following Exynos chips: W920, 1080, 980, 990, 850, 2200, 1330, or 1380
  2. Confirm cellular modem or WWAN is enabled
    Check device settings or system logs for active cellular/WWAN interface presence. On Android, check Settings > Network & Internet > SIM cards or examine /proc/sys/kernel/bootdebug for modem status
    Affected if Cellular/WWAN functionality is active on a device with an affected Exynos chipset
  3. Verify RLC AM protocol handling is in use
    Examine modem logs or cellular network connection details for RLC AM mode activity. This typically requires access to modem diagnostic logs (AT commands such as AT+CRLA or vendor-specific logs)
    Affected if The device maintains an active LTE/5G connection using RLC Acknowledged Mode (AM) on an affected Exynos chipset

A device is affected if it contains any of the listed Exynos chipsets (W920, 1080, 980, 990, 850, 2200, 1330, or 1380) and has cellular/WWAN functionality enabled, as all firmware versions of these chips contain the vulnerability in RLC AM PDU processing.

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 vendor-provided firmware/security updates from Samsung for affected devices. Since this is a hardware-level firmware issue in cellular modems, no configuration workarounds are available.

Fix this in Exynos W920 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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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-2025-26781 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