CVE-2021-1379: Cisco IP Phones Cisco Discovery Protocol and Link Layer Discovery Protocol Remote Code Execution and Denial of Service Vulnerabilities
Noroxi assessment
Priority: Monitor (action score 26/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.32% (FIRST EPSS).
- Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- According to the record, no fixed version is available yet.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Update when a fix is released; follow the vendor's advisory.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
Multiple vulnerabilities in the Cisco Discovery Protocol and Link Layer Discovery Protocol (LLDP) implementations for Cisco IP Phone Series 68xx/78xx/88xx could allow an unauthenticated, adjacent attacker to execute code remotely or cause a reload of an affected IP phone. These vulnerabilities are due to missing checks when the IP phone processes a Cisco Discovery Protocol or LLDP packet. An attacker could exploit these vulnerabilities by sending a malicious Cisco Discovery Protocol or LLDP packet to the targeted IP phone. A successful exploit could allow the attacker to execute code on the affected IP phone or cause it to reload unexpectedly, resulting in a denial of service (DoS) condition.Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
- Published
- Nov 18, 2024
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 25th percentile
- CWE
- CWE-120
Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · cisco
- 6.5
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:X/RC:X/E:X
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- No fixed version yet
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| cisco | ip conference phone 7832 firmware | cpe:2.3:o:cisco:ip_conference_phone_7832_firmware |
| cisco | ip conference phone 7832 with multiplatform firmware | cpe:2.3:o:cisco:ip_conference_phone_7832_with_multiplatform_firmware |
| cisco | ip conference phone 7832 | cpe:2.3:h:cisco:ip_conference_phone_7832 |
| cisco | ip conference phone 8832 firmware | cpe:2.3:o:cisco:ip_conference_phone_8832_firmware |
| cisco | ip conference phone 8832 with multiplatform firmware | cpe:2.3:o:cisco:ip_conference_phone_8832_with_multiplatform_firmware |
| cisco | ip conference phone 8832 | cpe:2.3:h:cisco:ip_conference_phone_8832 |
| cisco | ip phone 6821 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_6821_with_multiplatform_firmware |
| cisco | ip phone 6821 | cpe:2.3:h:cisco:ip_phone_6821 |
| cisco | ip phone 6841 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_6841_with_multiplatform_firmware |
| cisco | ip phone 6841 | cpe:2.3:h:cisco:ip_phone_6841 |
| cisco | ip phone 6851 with multiplatform firmware | cpe:2.3:o:cisco:ip_phone_6851_with_multiplatform_firmware |
| cisco | ip phone 6851 | cpe:2.3:h:cisco:ip_phone_6851 |
and 43 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco ip conference phone 7832 firmwarebefore 12.8\(1\)
- cisco ip conference phone 7832 firmware12.8(1)
- cisco ip conference phone 7832 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip conference phone 8832 firmwarebefore 12.8\(1\)
- cisco ip conference phone 8832 firmware12.8(1)
- cisco ip conference phone 8832 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 6821 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 6841 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 6851 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 6861 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 6871 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 7811 firmwarebefore 12.8\(1\)
- cisco ip phone 7811 firmware12.8(1)
- cisco ip phone 7811 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 7821 firmwarebefore 12.8\(1\)
- cisco ip phone 7821 firmware12.8(1)
- cisco ip phone 7821 with multiplatform firmwarebefore 11.3\(2\)
- cisco ip phone 7841 firmwarebefore 12.8\(1\)
- cisco ip phone 7841 firmware12.8(1)
- cisco ip phone 7841 with multiplatform firmwarebefore 11.3\(2\)
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 IP Phones with Multiplatform Firmware
- 11.1.2, 11.2.1, 11.2.3, 11.2.2, 11.2.3 MSR1-1, 11.1.2 MSR1-1, 11.1.1, 11.1.2 MSR3-1, 11.0.0, 11.1.1 MSR1-1, 11.0.1, 11.1.1 MSR2-1 … (+8)affected
Cisco Cisco Session Initiation Protocol (SIP) Software
- 9.0(3), 9.0(2)SR2, 9.0(2)SR1, 9.2(1), 9.4(2)SR1, 9.4(2), 9.4(2)SR2, 9.4(2)SR3, 9.3(1)SR2, 9.3(1)SR3, 9.3(1)SR1, 9.1(1)SR1 … (+28)affected
Cisco Cisco Small Business IP Phones
- 7.4.8, 7.4.3, 7.5.5a, 7.3.7, 7.5.2, 7.5.1, 7.4.6, 7.5.7, 7.4.4, 7.6.2SR3, 7.6.2, 7.5.6 … (+20)affected
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2020-3111Cisco IP Phone Remote Code Execution and Denial of Service Vulnerability36Monitor
- CVE-2019-1635Cisco IP Phone 7800 Series and 8800 Series Session Initiation Protocol XML Denial of Service Vulnerability31Monitor
- CVE-2019-1922Cisco IP Phone 7800 and 8800 Series Session Initiation Protocol Denial of Service Vulnerability30Monitor
Published before and after this one in the same product
- ← EarlierCVE-2021-34711Oct 6, 2021 · Cisco IP Phone Software Arbitrary File Read Vulnerability22Monitor
- ← EarlierCVE-2022-20660Jan 14, 2022 · Cisco IP Phones Information Disclosure Vulnerability18Monitor
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.
No history yet (it accumulates with the daily EPSS job).
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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-21-0194 · Mar 4, 2021(Cisco Güvenlik Güncellemesi Yayınladı)
Technical details
Attack conditions
- Someone on the same network segment 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
- Adjacent
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-120 · Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvd-secondary
Root cause
When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.
The bug in code
The whole CWE-120 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
char buf[256];
memcpy(buf, pkt->data, pkt->len);Fixed
char buf[256];
if (pkt->len > sizeof(buf)) {
return -EINVAL;
}
memcpy(buf, pkt->data, pkt->len);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
- 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
- Overflow Variables and TagsCAPEC-46likelihood: High · High
ATT&CK techniques
—
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Show all references (1 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.