A vulnerability in the quality of service (QoS) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, re
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.
- Published
- Mar 28, 2018
- Updated
- Jun 16, 2026
- EPSS
- 14.2% · 96th percentile
- CWE
- CWE-119
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Action score
73
This week
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- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 4 / 30 · 14.2%
CISA SSVC decision
- Exploitation
- active
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Mar 3, 2022. That signals real attacks, not theory.
Remediation deadline for government agencies: Mar 17, 2022.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | ios xe | cpe:2.3:o:cisco:ios_xe |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco ios xeall versions
- cisco ios xe16.5.1
Versions reported by the vendor
Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.
n/a Cisco IOS and IOS XE
- Cisco IOS and IOS XEaffected
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-20198Cisco is providing an update for the ongoing investigation into observed exploitation of the web UI feature in Cisco IOS XE Software.KEV100Now
- CVE-2023-20273A vulnerability in the web UI feature of Cisco IOS XE Software could allow an authenticated, remote attacker to inject commands with the priKEV85Now
- CVE-2025-20188A vulnerability in the Out-of-Band Access Point (AP) Image Download, the Clean Air Spectral Recording, and the client debug bundles features48Plan
- CVE-2019-12643Cisco REST API Container for IOS XE Software Authentication Bypass Vulnerability42Plan
- CVE-2018-0315A vulnerability in the authentication, authorization, and accounting (AAA) security services of Cisco IOS XE Software could allow an unauthe41Plan
- CVE-2017-12229A vulnerability in the REST API of the web-based user interface (web UI) of Cisco IOS XE 3.1 through 16.5 could allow an unauthenticated, re41Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- CISA KEV+1435 d
- TodaySep 29, 2026+3107 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- www.securityfocus.com/bid/103540
- www.securitytracker.com/id/1040582
- ics-cert.us-cert.gov/advisories/ICSA-18-107-03
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180328-qos
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-0151
Vendor advisories and official records. Exploit/PoC links are deliberately left out.