NVD / CVE Program· CNA cisco

CVE-2023-20259: A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to caus

Noroxi assessment

Priority: Monitor (action score 30/100)

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: 0.80% (FIRST EPSS); higher than 56.8% 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 the record, no fixed version is available yet.

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

A vulnerability in an API endpoint of multiple Cisco Unified Communications Products could allow an unauthenticated, remote attacker to cause high CPU utilization, which could impact access to the web-based management interface and cause delays with call processing. This API is not used for device management and is unlikely to be used in normal operations of the device. This vulnerability is due to improper API authentication and incomplete validation of the API request. An attacker could exploit this vulnerability by sending a crafted HTTP request to a specific API on the device. A successful exploit could allow the attacker to cause a denial of service (DoS) condition due to high CPU utilization, which could negatively impact user traffic and management access. When the attack stops, the device will recover without manual intervention.

HighCVSS 7.5 · v3.1—No exploit No fix recorded

BDU:2023-06444

Published: Oct 4, 2023
Updated: Jun 17, 2026
EPSS: 0.8% · 56th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 30 / 40 · 7.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.8%

CNA vs NVD score

NVD: 7.5
CNA · cisco: 8.6; 1.1 point gap

CVSS:3.1/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.

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.

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Affected 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	emergency responder	cpe:2.3:a:cisco:emergency_responder
cisco	prime collaboration deployment	cpe:2.3:a:cisco:prime_collaboration_deployment
cisco	unified communications manager	cpe:2.3:a:cisco:unified_communications_manager
cisco	unified communications manager im \& presence service	cpe:2.3:a:cisco:unified_communications_manager_im_\&_presence_service
cisco	unity connection	cpe:2.3:a:cisco:unity_connection

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

cisco emergency responder14su3
cisco prime collaboration deployment14su3
cisco unified communications manager12.5(1)su7
cisco unified communications manager14su3
cisco unified communications manager im & presence service12.5(1)su7
cisco unified communications manager im & presence service14su3
cisco unity connection14su3

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 Emergency Responder
- 12.5(1)SU7, 14, 14SU3affected
Cisco Cisco Prime Collaboration Deployment
- 14SU3affected
Cisco Cisco Unified Communications Manager
- 12.5(1)SU7, 12.5(1)SU7a, 14SU3affected
Cisco Cisco Unified Communications Manager IM and Presence Service
- 12.5(1)SU7, 14SU3affected
Cisco Cisco Unity Connection
- 14SU3affected

Same product

cisco: all records

Other highest-scoring records for the same primary product.

CVE-2008-1154The Disaster Recovery Framework (DRF) master server in Cisco Unified Communications products, including Unified Communications Manager (CUCM
42Plan
CVE-2017-12337A vulnerability in the upgrade mechanism of Cisco collaboration products based on the Cisco Voice Operating System software platform could a
41Plan
CVE-2004-1760The default installation of Cisco voice products, when running the IBM Director Agent on IBM servers before OS 2000.2.6, does not require au
41Plan

Published before and after this one in the same product

← EarlierCVE-2023-20266Aug 30, 2023 · A vulnerability in Cisco Emergency Responder, Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Sessio
28Monitor
← EarlierCVE-2023-20101Oct 4, 2023 · A vulnerability in Cisco Emergency Responder could allow an unauthenticated, remote attacker to log in to an affected device using the root
40Plan
Later →CVE-2024-20347Apr 3, 2024 · A vulnerability in Cisco Emergency Responder could allow an unauthenticated, remote attacker to conduct a CSRF attack, which could allow the
26Monitor

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 researchers

Finders, 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-400 · Uncontrolled Resource Consumption

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

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)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-apidos-PGsDcdNF

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records