CVE-2017-12238
A vulnerability in the Virtual Private LAN Service (VPLS) code of Cisco IOS 15.0 through 15.4 for Cisco Catalyst 6800 Series Switches could allow an unauthenticated, adjacent attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a denial of service (DoS) condition. The vulnerability is due to a memory management issue in the affected software. An attacker could exploit this vulnerability by creating a large number of VPLS-generated MAC entries in the MAC address table of an affected device. A successful exploit could allow the attacker to cause a C6800-16P10G or C6800-16P10G-XL type line card to crash, resulting in a DoS condition. This vulnerability affects Cisco Catalyst 6800 Series Switches that are running a vulnerable release of Cisco IOS Software and have a Cisco C6800-16P10G or C6800-16P10G-XL line card in use with Supervisor Engine 6T. To be vulnerable, the device must also be configured with VPLS and the C6800-16P10G or C6800-16P10G-XL line card needs to be the core-facing MPLS interfaces. Cisco Bug IDs: CSCva61927.
- CVSS
- 6.5Mediumscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Mar 2022CISA deadline for US federal agencies: 24 Mar 2022
- EPSS
- 2.0%chance of exploitation in the next 30 daystop 19% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 29 Sept 2017analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Cisco IOS | Cisco IOSVendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- cisco:ios
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. The attack does not come over the network, so a WAF is not on its path. Patching is the reliable fix.
Also consider: patch
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Mar 2022.
- CISA due date
- 24 Mar 2022, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation active, automatable no, technical impact partialAssessed by CISA 8 Nov 2024 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 29 Sept 2017Published
- 3 Mar 2022Added to CISA KEV (exploited in the wild)1,616 days (about 4 years) later
- 24 Mar 2022CISA remediation due date (US federal agencies)21 days later
- 8 Nov 2024CISA SSVC assessment: exploitation active961 days (about 3 years) later
- 12 Jan 2026CVE record last updated430 days (about 1 year) later
- 12 Nov 2026Analysed by vulneraibility.com304 days (about 10 months) later
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | AdjacentSame subnet or link layer. | Same subnet or link layer. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | NoneNo victim action needed. | No victim action needed. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | NoneNo data disclosure. | No data disclosure. |
| Integrity | NoneNo unauthorised modification. | No unauthorised modification. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2017-12238 being exploited?
Yes. CVE-2017-12238 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2017-12238?
CVE-2017-12238 is rated Medium with a CVSS score of 6.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2017-12238?
Yes. A fix has been recorded for CVE-2017-12238. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2017-12238 affect?
CVE-2017-12238 affects cisco:ios. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
4 references in the CVE record, grouped by the tags the record gives them.
Other links (4)
- securitytracker.com /id/1039453
- securityfocus.com /bid/101040
- tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-20170927-vpls
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-12238
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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