Cisco StarOS Denial of Service Vulnerability
A vulnerability in the internal packet-processing functionality of the Cisco StarOS operating system running on virtual platforms could allow an unauthenticated, remote attacker to cause an affected device to stop processing traffic, resulting in a denial of service (DoS) condition. The vulnerability is due to a logic error that may occur under specific traffic conditions. An attacker could exploit this vulnerability by sending a series of crafted packets to an affected device. A successful exploit could allow the attacker to prevent the targeted service interface from receiving any traffic, which would lead to a DoS condition on the affected interface. The device may have to be manually reloaded to recover from exploitation of this vulnerability.
- Published
- Jun 19, 2019
- Updated
- Jun 16, 2026
- EPSS
- 2.6% · 85th percentile
- CWE
- CWE-824
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.6%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · cisco
- 8.6
- 1.1 point gap
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | staros | cpe:2.3:o:cisco:staros |
| cisco | asr 5000 | cpe:2.3:h:cisco:asr_5000 |
| cisco | asr 5500 | cpe:2.3:h:cisco:asr_5500 |
| cisco | asr 5700 | cpe:2.3:h:cisco:asr_5700 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco staros21.6 and later · before 21.6.13
- cisco staros21.6b and later · before 21.6b.16
- cisco staros21.7 and later · before 21.7.11
- cisco staros21.8 and later · before 21.8.10
- cisco staros21.9 and later · before 21.9.7
- cisco staros21.10 and later · before 21.10.2
- cisco staros21.11 and later · before 21.11.1
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.
Cisco Cisco ASR 5000 Series Software
- unspecified and later · before 21.11.1affected
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-20046A vulnerability in the key-based SSH authentication feature of Cisco StarOS Software could allow an authenticated, remote attacker to elevat35Monitor
- CVE-2021-1539Cisco ASR 5000 Series Software Authorization Bypass Vulnerabilities35Monitor
- CVE-2018-0369A vulnerability in the reassembly logic for fragmented IPv4 packets of Cisco StarOS running on virtual platforms could allow an unauthentica35Monitor
- CVE-2021-1353Cisco StarOS IPv4 Denial of Service Vulnerability34Monitor
- CVE-2020-3500Cisco StarOS IPv6 Denial of Service Vulnerability34Monitor
- CVE-2017-6707A vulnerability in the CLI command-parsing code of the Cisco StarOS operating system for Cisco ASR 5000 Series 11.0 through 21.0, 5500 Serie32Monitor
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
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-824 · Access of Uninitialized PointerCVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- www.securityfocus.com/bid/108853
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190619-staros-asr-dos
Vendor advisories and official records. Exploit/PoC links are deliberately left out.