High Memory corruption

CVE-2025-20350 — Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Firmware Denial of Service Vulnerability

A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 running Cisco SIP Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to a buffer overflow when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending crafted HTTP input to the device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To exploit this vulnerability, the phone must be registered to Cisco Unified Communications Manager and have Web Access enabled. Web Access is disabled by default.

Published Oct 15, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.5% (30-day exploitation probability)+6
Technical severity (high)+6
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.48%

ahead of 40% of scored CVEs · Oct 15, 2026

Affects

Cisco

Cisco Session Initiation Protocol (SIP) Software and 17 more

CVSS base

7.5

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Cisco Cisco Session Initiation Protocol (SIP) Software, Cisco Desk Phone 9841 Firmware, Cisco Desk Phone 9851 Firmware…).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Cisco	Cisco Session Initiation Protocol (SIP) Software	version 2.3(1)version 14.0(1)SR3version 11.0(6)SR2version 14.1(1)SR1version 14.1(1)SR2version 11.0(6)SR4version 14.2(1)version 14.2(1)SR1 and 88 more version 11.0(6)SR5version 14.1(1)SR3version 14.2(1)SR2version 3.1(1)version 3.0(1)version 14.1(1)version 2.3(1)SR1version 2.2(1)version 2.1(1)version 2.0(1)version 14.2(1)SR3version 3.1(1)SR1version 14.3(1)version 3.2(1)version 14.3(1)SR1version 14.2(1)SR4version 11.0(6)SR6version 11.0(5)SR1version 11.0(4)SR3version 11.0(5)version 11.0(3)SR2version 11.0(3)SR4version 11.0(3)SR3version 11.0(2)SR2version 11.0(4)SR1version 11.0(5)SR3version 11.0(3)version 11.0(5)SR2version 11.0(3)SR6version 11.0(2)version 11.0(4)SR2version 11.0(3)SR1version 11.0(3)SR5version 11.0(6)version 12.8(1)SR1version 12.8(1)SR2version 14.0(1)version 14.0(1)SR1version 11.0(6)SR1version 10.3(1)SR7version 14.0(1)SR2version 12.1(1)SR1version 11.5(1)version 10.3(2)version 10.2(2)version 10.3(1)version 10.3(1)SR4version 11.0(1)version 10.4(1)SR2 3rd Partyversion 11.7(1)version 12.1(1)version 11.0(0.7) MPPversion 9.3(4) 3rd Partyversion 12.5(1)SR2version 10.2(1)SR1version 9.3(4)SR3 3rd Partyversion 10.2(1)version 12.5(1)version 10.3(1)SR2version 11-0-1MSR1-1version 10.4(1) 3rd Partyversion 12.5(1)SR1version 11.5(1)SR1version 10.1(1)SR2version 12.0(1)SR2version 12.6(1)version 10.3(1.11) 3rd Partyversion 12.0(1)version 12.0(1)SR1version 9.3(3)version 12.5(1)SR3version 10.3(1)SR4bversion 9.3(4)SR1 3rd Partyversion 10.3(1)SR5version 10.1(1.9)version 10.3(1.9) 3rd Partyversion 9.3(4)SR2 3rd Partyversion 10.3(1)SR1version 10.3(1)SR3version 10.1(1)SR1version 12.0(1)SR3version 12.6(1)SR1version 12.7(1)version 10.3(1)SR6version 12.8(1)version 12.7(1)SR1version 11.0(2)SR1version 11.0(4)	Vulnerable	CVE Program (cve.org) e CISA ADP
Cisco	Desk Phone 9841 Firmware	≥ 3.0\(1\) and ≤ 3.2\(1\)	Vulnerable	NIST National Vulnerability Database
Cisco	Desk Phone 9851 Firmware	≥ 3.0\(1\) and ≤ 3.2\(1\)	Vulnerable	NIST National Vulnerability Database
Cisco	Desk Phone 9861 Firmware	≥ 3.0\(1\) and ≤ 3.2\(1\)	Vulnerable	NIST National Vulnerability Database
Cisco	Desk Phone 9871 Firmware	≥ 3.0\(1\) and ≤ 3.2\(1\)	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 7811 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 7821 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 7841 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 7861 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8811 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8821 Firmware	< 11.0\(1\)version 11.0(0.7)-mppversion 11.0(1)version 11.0(2)version 11.0(2)-sr1version 11.0(2)-sr2version 11.0(3)version 11.0(3)-sr1 and 19 more version 11.0(3)-sr2version 11.0(3)-sr3version 11.0(3)-sr4version 11.0(3)-sr5version 11.0(3)-sr6version 11.0(4)version 11.0(4)-sr1version 11.0(4)-sr2version 11.0(4)-sr3version 11.0(5)version 11.0(5)-sr1version 11.0(5)-sr2version 11.0(5)-sr3version 11.0(6)version 11.0(6)-sr1version 11.0(6)-sr2version 11.0(6)-sr4version 11.0(6)-sr5version 11.0(6)-sr6	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8832 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8841 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8845 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8851 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8861 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Ip Phone 8865 Firmware	< 14.3\(1\)version 14.3(1)version 14.3(1)-sr1	Vulnerable	NIST National Vulnerability Database
Cisco	Video Phone 8875 Firmware	< 2.3\(1\)≥ 3.0\(1\) and ≤ 3.2\(1\)version 2.3(1)version 2.3(1)-sr1	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.5	CVSS 3.1	High	3.9	3.6	psirt@cisco.com via NIST National Vulnerability Database
7.5	CVSS 3.1	High	—	—	cisco via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-121 · Stack-based Buffer Overflow

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.48%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products added · cisco/cisco session initiation protocol (sip) software
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 7.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Oct 15, 2025 · cisco

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-dos-FPyj
Vendor Advisory, NIST National Vulnerability Database

Elsewhere on this site

Cisco
every CVE for this vendor

Memory corruption
same class

CWE-121
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-20281 Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability Sep 2, 2026
Medium CVE-2025-20351 Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Firmware Cross-Site Scripting Vulnerability Oct 15, 2025
Medium CVE-2020-26140 Use of a Broken or Risky Cryptographic Algorithm in Alfa Awus036h Firmware May 11, 2021
Low CVE-2020-24588 The 802.11 standard that underpins Wi-Fi Protected Access (WPA, WPA2, and WPA3) and Wired... May 11, 2021
Critical CVE-2020-3161 Cisco IP Phones Web Server Remote Code Execution and Denial-of-Service Vulnerability KEV Apr 15, 2020

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-20350 is "Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Firmware Denial of Service Vulnerability", rated High. It affects Cisco Session Initiation Protocol (SIP) Software (Cisco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.5 describes technical severity. EPSS 0.48% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.