CVE-2025-20248
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 vulnerability in the installation process of Cisco IOS XR Software could allow an authenticated, local attacker to bypass Cisco IOS XR Software image signature verification and load unsigned software on an affected device. To exploit this vulnerability, the attacker must have root-system privileges on the affected device. This vulnerability is due to incomplete validation of files during the installation of an .iso file. An attacker could exploit this vulnerability by modifying contents of the .iso image and then installing and activating it on the device. A successful exploit could allow the attacker to load an unsigned file as part of the image activation process.
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 vulnerability in the installation process of Cisco IOS XR Software allows an authenticated local attacker with root-system privileges to bypass image signature verification by modifying the contents of an .iso image file and then installing and activating it, enabling unsigned files to be loaded onto the affected device.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- None
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
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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Identify if the device runs Cisco IOS XR SoftwareExecute 'show version' or 'show install active' on the device CLI to confirm the operating system is Cisco IOS XR.Affected if The device is running any version of Cisco IOS XR Software.
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Determine the installed IOS XR versionRun 'show version' and note the exact software version string (for example, 7.x.y). Compare this version to any official Cisco advisory for CVE-2025-20248 to see if it falls within an affected range.Affected if The installed version matches a version known to be affected by this vulnerability (check Cisco advisories for specific version ranges).
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Check if .iso image installation is permittedReview the device configuration for any install-related commands or AAA authorization settings that control .iso image loading. Use 'show running-config | include install' to view install-related configuration.Affected if The device allows installation from .iso images and the attacker has root-system privileges to perform the install.
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Audit recent install/activation operationsUse 'show install log' or 'show logging' to review recent installation activities. Look for any installation or activation events involving .iso files.Affected if There are records of .iso image installations or activations performed on the device.
The device is affected if it runs Cisco IOS XR Software and an attacker with root-system privileges can install or activate a modified .iso image on the system.
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.
From vendor dataApply the vendor-provided patch when available. Until then, restrict root-system access to trusted personnel only and verify integrity of all IOS XR software images before installation using official Cisco distribution channels.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-20248 — 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-2025-20248 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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