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CISA KEV · ACTIVELY EXPLOITED
CRITICAL severity

CVE-2018-0151

CRITICAL

CVE-2018-0151 is a critical-severity (CVSS 9.8) Buffer Overflow vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-03) — treat it as actively exploited and patch now. O3 Security confirms whether CVE-2018-0151 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service…

Published
Mar 28, 2018
Updated
Jan 12, 2026
Affected
0 pkgs
Patched
None yet
Exploits
2 known
Exploitation data as of Aug 26, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-03-03. Federal agencies were required to remediate by 2022-03-17.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2018-0151.

EPSS Exploitation Probability

via FIRST.org ↗
14.3%probability of exploitation in next 30 days
Moderate Risk-0.18%
Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk
3.27%7.86%12.5%17.1%5.9%14.3%Feb 26Jun 26Aug 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2018-0151 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 368,770 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Description

A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges. The vulnerability is due to incorrect bounds checking of certain values in packets that are destined for UDP port 18999 of an affected device. An attacker could exploit this vulnerability by sending malicious packets to an affected device. When the packets are processed, an exploitable buffer overflow condition may occur. A successful exploit could allow the attacker to execute arbitrary code on the affected device with elevated privileges. The attacker could also leverage this vulnerability to cause the device to reload, causing a temporary DoS condition while the device is reloading. The malicious packets must be destined to and processed by an affected device. Traffic transiting a device will not trigger the vulnerability. Cisco Bug IDs: CSCvf73881.

Exploits & PoCs
2

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of the affected component has shipped for CVE-2018-0151 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2018-0151 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2018-0151. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with elevated privileges. The vulnerability is due to incorrect bounds checking of certain values in packets that are destined for UDP port 18999 of an affected device. An attacker could exploit this vulnerability by sending malicious packets to an affected device. When the packets are processed, an exploitable buffer overflow condition may occur. A successful exploit coul
O3 Security · Impact-Aware SCA

Is CVE-2018-0151 in your dependencies?

O3 detects CVE-2018-0151 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2018-0151: Buffer Overflow (Critical 9.8) | O3 Security