CVE-2026-103101

Executive Summary

CVE-2026-103101 is an improper input validation vulnerability (CWE-770, allocation of resources without limits or throttling) in the web server component of Pexip Infinity versions 30.0 through 40.x before 41.0. A remote, unauthenticated attacker can exploit this flaw to render a Pexip Infinity node inaccessible, resulting in a denial-of-service condition affecting video conferencing and collaboration services. With a CVSS v3.1 base score of 8.6, the vulnerability is network-reachable, requires no privileges or user interaction, and has a high availability impact that can propagate beyond the vulnerable node due to the changed scope characteristic.

Technical Analysis

The vulnerability resides in the web server of Pexip Infinity, a video conferencing and collaboration platform. The NVD description states that the issue is "improper input validation in the web server that allows a malicious attacker to render a Pexip Infinity node inaccessible." The assigned CWE-770 ("Allocation of Resources Without Limits or Throttling") indicates the core mechanism: the web server fails to properly validate or bound input in a way that permits an attacker to consume resources without limit or throttling.

In practical terms, improper input validation combined with unlimited resource allocation means the web server can be driven into a state where it can no longer service legitimate requests — for example, by processing inputs that exhaust memory, connection handlers, worker threads, or similar finite resources. Because the description explicitly frames the outcome as a node becoming "inaccessible," this is a denial-of-service/availability class flaw rather than one leading to code execution or data disclosure. The CVSS subscore for Confidentiality is None (C:N) and Integrity is None (I:N), consistent with an availability-only impact.

Scope is marked as Changed (S:C). This means the exploited vulnerability in the web server component can affect resources beyond its own security scope — for instance, impacting the broader Infinity node or dependent conferencing services that rely on the web server being reachable.

The weakness class CWE-770 is important for defenders: rather than a memory-safety overflow, the issue is an unbounded-resource-consumption condition. This class typically manifests as missing or insufficient rate limiting, request-size caps, connection limits, or input normalization before the value is used to allocate compute/memory. However, the NVD description does not disclose the specific request parameter, endpoint, or parsing routine involved. Per accuracy rules, no specific function, endpoint, or parameter names are asserted here; they are not provided in the source data.

Affected versions: Pexip Infinity 30.0 through 40.x, with 41.0 designated as the first mitigating release line per the NVD description ("before 41.0"). No public proof-of-concept, exploit code, or Nuclei template is currently tracked, and the CVE is not listed in CISA KEV as of this report. EPSS has not yet scored this CVE by FIRST.org; no EPSS value should be assumed.

Exploitation Scenarios

The following attack chain is inferred at the vulnerability-class level (improper input validation / unbounded resource allocation) because no public PoC or technical write-up is available.

1. Reconnaissance / target identification. An attacker enumerates internet-facing or internal Pexip Infinity deployments. Because Pexip Infinity web servers are commonly exposed to support management, conferencing portals, or administrative access, discovery can be performed by scanning for hosts running vulnerable versions (30.0 through 40.x) and identifying the web service via banner/fingerprint techniques. Pre-auth reachability is consistent with the CVSS vector (AV:N/PR:N/UI:N).

2. Triggering the specific flaw class. The attacker sends crafted HTTP input to the web server that is not properly validated and that causes unbounded allocation/consumption of a finite resource. Because the exact parameter/endpoint is not disclosed in the source data, no specific request structure is asserted. At the class level, this is a request that the server accepts and processes without an adequate limit or throttle.

3. Payload/execution method. No code execution is required. The attacker need only deliver the malformed or resource-amplifying request, likely repeatedly or at high volume, to exhaust the targeted resource pool on the node. Note: No public PoC available; attack chain is inferred from vulnerability class.

4. Post-exploitation impact. Successful exploitation renders the Pexip Infinity node inaccessible. Because scope is Changed (S:C), availability impact can extend to conferencing and dependent services that rely on that node, disrupting video meetings and collaboration. Confidentiality and integrity are not impacted per the CVSS vector.

Impact Assessment

• Base severity: CVSS v3.1 8.6 (High). Vector: AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
• Attack Vector (Network): exploitable remotely, broadening the pool of potential attackers.
• Attack Complexity (Low) and Privileges Required (None) and User Interaction (None): exploitation is straightforward for an unauthenticated remote actor with a network path to the web server.
• Scope (Changed): the flaw can affect resources beyond the vulnerable web server component, raising severity above what an availability-only, same-scope bug would carry.
• Confidentiality: None. Integrity: None. Availability: High — the primary and defining business impact.

Business impact centers on service outage: video conferencing and collaboration depend on Pexip Infinity nodes being reachable. An inaccessible node can disrupt scheduled meetings, emergency communications, and internal/external conferencing. Blast radius depends on deployment topology — a single-node deployment suffers total loss of conferencing capability, while clustered/multi-node deployments may degrade gracefully or be clustered around the node if ingress/load-balancing permits. The Changed Scope rating suggests defenders should not assume isolation to the web server alone.

Exploitability caveats: No public exploit, PoC, or Nuclei template is available, and the CVE is not currently in CISA KEV. EPSS is unscored. Absence of public exploit code does not reduce the technical ease implied by AC:L/PR:N/UI:N, particularly for availability-flooding style attacks that are trivial to script once the input vector is discovered.

Detection Guidance

Detection should focus on anomalous request rates/patterns targeting Pexip Infinity web servers, sudden resource exhaustion on hosting nodes, and node unavailability events. Because the specific input parameter is undisclosed, detections are behavior-based and version/asset-centric rather than signature-precise. Tune thresholds to each environment.

Sigma Rule

title: Potential Pexip Infinity Web Server Resource Exhaustion (CVE-2026-103101)
id: 9b2f1c74-0a3e-4d51-9c8e-7f6a1b2c3d40
status: experimental
description: Detects HTTP request floods or abnormal request rates to Pexip Infinity web services that may indicate exploitation of CWE-770 improper input validation leading to node inaccessibility.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-103101
author: Valters IT Threat Intelligence
date: 2026/01/01
logsource:
  category: webserver
detection:
  selection_pexip:
    cs-uri-host|contains:
      - 'pexip'
  selection_status:
    sc-status:
      - 500
      - 502
      - 503
      - 504
      - 408
  timeframe: 5m
  condition: selection_pexip and selection_status | count() by src_ip > 100
fields:
  - src_ip
  - cs-uri-host
  - cs-uri-stem
  - sc-status
falsepositives:
  - Legitimate load balancer health checks
  - Monitoring probes during maintenance
level: high

YARA Rule

rule CVE_2026_103101_Pexip_Resource_Exhaustion
{
    meta:
        description = "Heuristic detection of high-volume or malformed HTTP requests targeting Pexip Infinity web server (CVE-2026-103101, CWE-770)"
        author = "Valters IT Threat Intelligence"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-103101"
        date = "2026-01-01"
        severity = "high"

    strings:
        $pexip = "Pexip" ascii nocase
        $infinity = "Infinity" ascii nocase
        $http_get = "GET /" ascii
        $http_post = "POST /" ascii
        $beacon = "User-Agent: " ascii

    condition:
        uint16(0) == 0x4854 and
        (any of ($http_get, $http_post)) and
        any of ($pexip, $infinity) and
        #beacon > 1
}

Suricata IDS Rule

alert http any any -> any any (msg:"CVE-2026-103101 Potential Pexip Infinity Web Server Resource Exhaustion Attempt"; flow:to_server,established; http.header; content:"Host"; nocase; pcre:"/Host\x3a[^\r\n]*pexip/i"; threshold:type both, track by_src, count 100, seconds 10; classtype:attempted-dos; sid:2026103101; rev:1; reference:cve,2026-103101; metadata:affected_product Pexip_Infinity, attack_target Server, deployment Perimeter, signature_severity Major, created_at 2026_01_01;)

Elastic Detection

sequence by source.ip with maxspan=10s
  [ network where network.protocol == "http" and
      http.request.method in ("GET", "POST") and
      url.domain : "*pexip*" ]
  [ network where network.protocol == "http" and
      http.response.status_code in (408, 429, 500, 502, 503, 504) and
      url.domain : "*pexip*" ]

Splunk SPL Query

index=web OR index=proxy (host=*pexip* OR url=*pexip*)
| where status IN (408, 429, 500, 502, 503, 504)
| bin _time span=1m
| stats count AS req_count dc(url) AS distinct_urls values(status) AS statuses by src_ip _time
| where req_count > 100
| sort - req_count
| table _time src_ip req_count distinct_urls statuses

Wazuh OSSEC Rule

<group name="web,pexip,cve-2026-103101,">
  <rule id="103101" level="10">
    <if_sid>31100</if_sid>
    <field name="url">\.pexip|/pexip</field>
    <description>CVE-2026-103101: Suspicious HTTP request targeting Pexip Infinity web server (possible resource exhaustion attempt).</description>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>

  <rule id="103102" level="12">
    <if_sid>31101,31103,31106</if_sid>
    <field name="id">408|429|500|502|503|504</field>
    <description>CVE-2026-103101: Pexip Infinity web server returned availability-impacting status under anomalous request volume; possible denial of service.</description>
    <mitre>
      <id>T1499</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). Note: the NVD description identifies 41.0 as the release line that resolves the issue ("before 41.0"), but no vendor advisory or patch reference is available in the tracked sources, so patch status cannot be independently confirmed.

1. Immediate mitigations (until upgrade to 41.0 is performed):

• Restrict network access to Pexip Infinity web server interfaces using firewall rules, ACLs, or security groups; permit only trusted management and conferencing networks. This directly reduces the AV:N exposure surface.
• Place Pexip web services behind a reverse proxy or WAF configured with request-rate limiting, connection limits, and request-size caps to enforce the throttling that the vulnerable component lacks (CWE-770 mitigation).
• Enable and tune rate limiting at the load balancer edge for requests to Pexip nodes.
• Monitor node resource utilization (CPU, memory, connection counts) and configure alerting on saturation and on repeated 5xx responses.
• Consider placement/isolation to limit the Changed-Scope impact on dependent conferencing services.

2. Patch/upgrade steps:

• Upgrade Pexip Infinity to version 41.0 or later. Treat 41.0 as the target version per the NVD statement that versions "before 41.0" are affected.
• Validate the exact supported upgrade path and prerequisites against Pexip's official release notes/documentation before production rollout; no patch reference is available in the tracked data, so verify the current vendor advisory directly.
• After upgrade, re-test web server availability under load and confirm that rate-limiting/validation behavior behaves as expected.

3. Long-term hardening:

• Adopt a patch-management SLA for internet-facing collaboration infrastructure with rapid rollout of vendor security releases.
• Deploy WAF/IPS protections with rate-limiting as a persistent control, not just a temporary workaround.
• Implement defense-in-depth segmentation so a single node failure does not cascade (S:C), including healthy multi-node clustering and load balancing with failover.
• Continuously inventory Pexip Infinity versions and use fingerprint-based scanning (e.g., Shodan/Censys style) internally to detect out-of-date, exposed instances.
• Include CWE-770 input-validation and resource-throttling checks in secure-deployment reviews for any public-facing service.

References

• NVD — CVE-2026-103101: https://nvd.nist.gov/vuln/detail/CVE-2026-103101
• CWE-770: Allocation of Resources Without Limits or Throttling: https://cwe.mitre.org/data/definitions/770.html
• Pexip Infinity product documentation and release notes (verify current advisory for version 41.0): https://docs.pexip.com/
• FIRST EPSS: not yet scored for this CVE (do not assume a value): https://www.first.org/epss/
• CISA Known Exploited Vulnerabilities Catalog: CVE-2026-103101 not currently listed: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Threat actor attribution and exploit-in-the-wild evidence: none available. No public PoC, exploit code, or Nuclei template is tracked, and the CVE is not listed in CISA KEV as of this report.