Cisco IP Phones Web Server Remote Code Execution and Denial of Service Vulnerability
Noroxi assessment
Priority: Now (action score 94/100)
- CISA has confirmed exploitation in the wild (Nov 3, 2021). Remediation deadline for US federal agencies: May 3, 2022.
- Probability of exploitation in the next 30 days: 83.8% (FIRST EPSS); higher than 99.6% of all records.
- 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.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- According to the record, no fixed version is available yet.
Patch today or shut off access. Until a fix is released, restrict access to the affected component and 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 · CISA KEV · FIRST EPSS
A vulnerability in the web server for Cisco IP Phones could allow an unauthenticated, remote attacker to execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. The vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web server of a targeted device. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a DoS condition.
- Published
- Apr 15, 2020
- Updated
- Jun 16, 2026
- EPSS
- 83.8% · 99th percentile
- CWE
- CWE-20
Report tools
Action score
94
Now
Patch today or shut off access.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 25 / 30 · 83.8%
CISA SSVC decision
- Exploitation
- active
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 9.8
- CNA · cisco
- 9.8
- agree
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.
Remediation deadline for US federal agencies: May 3, 2022.
Get told when this record changes
- In CISA KEV: exploitation in the wild confirmed
- Weaponized exploit exists
- 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 phone 8865 firmware | cpe:2.3:o:cisco:ip_phone_8865_firmware |
| cisco | ip phone 8865 | cpe:2.3:h:cisco:ip_phone_8865 |
| cisco | ip phone 8851 firmware | cpe:2.3:o:cisco:ip_phone_8851_firmware |
| cisco | ip phone 8851 | cpe:2.3:h:cisco:ip_phone_8851 |
| cisco | ip phone 7841 firmware | cpe:2.3:o:cisco:ip_phone_7841_firmware |
| cisco | ip phone 7841 | cpe:2.3:h:cisco:ip_phone_7841 |
| cisco | ip phone 7821 firmware | cpe:2.3:o:cisco:ip_phone_7821_firmware |
| cisco | ip phone 7821 | cpe:2.3:h:cisco:ip_phone_7821 |
| cisco | ip phone 8811 firmware | cpe:2.3:o:cisco:ip_phone_8811_firmware |
| cisco | ip phone 8811 | cpe:2.3:h:cisco:ip_phone_8811 |
| cisco | ip phone 8861 firmware | cpe:2.3:o:cisco:ip_phone_8861_firmware |
| cisco | ip phone 8861 | cpe:2.3:h:cisco:ip_phone_8861 |
and 14 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco 8831 firmware10.3(1)es14
- cisco 8831 firmware11.0(1)
- cisco 8831 firmware11.0(5)sr1
- cisco ip phone 7811 firmware11.0(1)
- cisco ip phone 7821 firmware11.0(1)
- cisco ip phone 7841 firmware11.0(1)
- cisco ip phone 7861 firmware11.0(1)
- cisco ip phone 8811 firmware10.3(1)es14
- cisco ip phone 8811 firmware11.0(1)
- cisco ip phone 8811 firmware11.0(5)sr1
- cisco ip phone 8821 firmware10.3(1)es14
- cisco ip phone 8821 firmware11.0(1)
- cisco ip phone 8821 firmware11.0(5)sr1
- cisco ip phone 8821-ex firmware10.3(1)es14
- cisco ip phone 8821-ex firmware11.0(1)
- cisco ip phone 8821-ex firmware11.0(5)sr1
- cisco ip phone 8841 firmware10.3(1)es14
- cisco ip phone 8841 firmware11.0(1)
- cisco ip phone 8841 firmware11.0(5)sr1
- cisco ip phone 8845 firmware10.3(1)es14
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 phone
- n/aaffected
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.
Evidence
- Exploit-DB entry ×1
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | dos | 2020-04-17 |
| Proof-of-concept repository on GitHub | stars:0 | 2020-12-31 |
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
- First PoC+1 d
- CISA KEV+566 d
- TodayOct 16, 2026+2375 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-20 · Improper Input ValidationCVSS 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
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
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.