dbcve.org
Asr 5000 Series SoftwareOperating system · Cisco

CVE-2018-0256

MEDIUM · 5.8 CVSS v3.0 Published 2018-04-19
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
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
A vulnerability in the peer-to-peer message processing functionality of Cisco Packet Data Network Gateway could allow an unauthenticated, remote attacker to cause the Session Manager (SESSMGR) process on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to incorrect validation of peer-to-peer packet headers. An attacker could exploit this vulnerability by sending a crafted peer-to-peer packet through an affected device. A successful exploit could allow the attacker to cause the SESSMGR process on the affected device to restart unexpectedly, which could briefly impact traffic while the SESSMGR process restarts and result in a DoS condition. Cisco Bug IDs: CSCvg88786.

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 Cisco Packet Data Network Gateway's peer-to-peer message processing allows unauthenticated remote attackers to send crafted packets with malformed headers that cause the Session Manager (SESSMGR) process to restart unexpectedly, resulting in denial of service. The root cause is incorrect validation of peer-to-peer packet headers.

MitigationApply the vendor patch from Cisco (refer to CSCvg88786) to fix the peer-to-peer packet header validation issue. If no patch is available, consider filtering or rate-limiting peer-to-peer traffic at network boundaries.

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
Asr 5000 Series SoftwareOperating system
Affected:= 20.3.0.66671= p2p_2.16.879

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
Changed
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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. Verify Cisco Asr 5000 Series is deployed
    Confirm the target system is a Cisco Asr 5000 Series gateway by checking the device model via 'show hardware' or 'show version' command output
    Affected if The device is NOT a Cisco Asr 5000 Series, as this CVE only affects that platform
  2. Check installed software version
    Run 'show version' or 'show software' and locate the StarOS software version string. Look for exact version 20.3.0.66671 or p2p_2.16.879 in the version output
    Affected if The installed version exactly matches 20.3.0.66671 or p2p_2.16.879
  3. Verify peer-to-peer feature is enabled
    Run 'show peer-to-peer status' or 'show configuration peer-to-peer' to check if the P2P messaging feature is configured and active on the system
    Affected if Peer-to-peer messaging is enabled, as the vulnerability is triggered by crafted P2P packets with malformed headers
  4. Check SESSMGR process availability
    Run 'show process sessmgr' to confirm the Session Manager process is running and accessible. The vulnerability causes this process to restart when malformed P2P packets are received
    Affected if SESSMGR process is running and the system accepts peer-to-peer traffic from untrusted sources

A system is affected if it is a Cisco Asr 5000 Series running version 20.3.0.66671 or p2p_2.16.879 with the peer-to-peer messaging feature enabled and exposed to network traffic.

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 the vendor patch from Cisco (refer to CSCvg88786) to fix the peer-to-peer packet header validation issue. If no patch is available, consider filtering or rate-limiting peer-to-peer traffic at network boundaries.

Fix this in Asr 5000 Series Software Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,100
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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-2018-0256 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