CVE-2026-103100

Executive Summary

CVE-2026-103100 is an improper input validation vulnerability in the signaling implementation of Pexip Infinity video conferencing platform versions prior to 40.1, allowing an unauthenticated remote attacker to trigger a software abort (process crash) and cause a denial of service. Organizations running self-hosted or cloud-managed Pexip Infinity deployments below version 40.1 are affected. The impact is availability-focused: a single crafted signaling message can terminate a critical conferencing service component, disrupting meetings and dependent communications workflows.

Technical Analysis

The NVD description states that Pexip Infinity before 40.1 "is affected by improper input validation in the signaling implementation that allows a malicious attacker to trigger a software abort resulting in a denial of service." This maps directly to CWE-617 (Reachable Assertion), which describes conditions where a product contains an assertion that can be triggered by an attacker, typically causing an abrupt process termination.

Pexip Infinity is a real-time communications platform that relies heavily on signaling protocols for session establishment, call routing, and media negotiation. Signaling components in such platforms continuously parse inbound protocol messages from remote peers — including SIP, H.323, and WebRTC signaling traffic depending on deployment configuration. Because these messages are received from potentially untrusted network sources (and in many deployments from the public internet to support external participants), the signaling parser represents an exposed attack surface.

The root cause class is improper input validation: the signaling implementation fails to adequately validate an attacker-controllable field before passing it to a code path that enforces a strict internal invariant. When that invariant is violated, the process aborts. Per CWE-617, the abort is an intentional safety construct (assertion) rather than memory corruption — the process terminates deliberately rather than continuing in an undefined state. This is a reliability and availability defect rather than a confidentiality or integrity issue.

Note on scope: The NVD description does not identify the specific protocol message, field, function, or parser involved. No CNA title, no affected-version enumeration, and no vendor advisory text were provided beyond the "before 40.1" threshold. The analysis above is therefore framed at the vulnerability-class level. No specific function names, endpoints, protocol parameters, or code paths are asserted here because none appear verbatim in the source data.

The CVSS v3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) confirms: network-reachable, low complexity, no privileges, no user interaction, unchanged scope, no confidentiality impact, no integrity impact, and high availability impact — consistent with a remotely triggerable crash.

Exploitation Scenarios

No public proof-of-concept, exploit code, or Nuclei template exists for this CVE at the time of writing. The attack chain below is inferred strictly from the vulnerability class (improper input validation leading to a reachable assertion / abort) and the CVSS vector; no implementation-specific details are invented.

1. Reconnaissance / target identification. An attacker identifies internet-facing or network-reachable Pexip Infinity deployments. Because the platform supports external participant connectivity, signaling listeners may be reachable from untrusted networks. Fingerprinting can leverage TLS certificate subjects, HTTP response characteristics, or protocol banner/greeting behavior typical of the deployment. The attacker must determine that the target version is below 40.1, since the flaw is version-gated.

2. Triggering the flaw class. The attacker sends a crafted signaling message to the exposed signaling interface. The message carries an input value that the pre-40.1 parser does not validate correctly. Per CWE-617, that malformed or out-of-range input reaches an assertion that evaluates false, and the process aborts. The attacker does not need credentials (PR:N) and does not need a victim to interact (UI:N), and no special conditions are required (AC:L).

3. Payload / execution method. At the vulnerability-class level, the payload is a protocol-level signaling message with an invalid or unexpected field value delivered to the vulnerable parser. No specific field name, message type, or byte pattern is described in the available data, and none is asserted here. The distinguishing characteristic is that the message is syntactically deliverable but semantically violates an input constraint the code fails to enforce before asserting.

4. Post-exploitation impact. The immediate result is process termination — availability loss (A:H). If the signaling component is supervised, it may restart, producing a brief outage; if it is not, or if the abort cascades to dependent components, the disruption is longer. An attacker with sustained access to the interface could repeat the trigger to maintain a degraded or offline state (a persistent denial-of-service condition), which is the primary operational risk given the absence of any confidentiality or integrity impact.

Impact Assessment

Business impact centers on availability of real-time communications. Pexip Infinity commonly underpins enterprise video conferencing, unified communications integration, and sometimes emergency or customer-facing meeting services. An abort in a signaling component can drop active sessions, prevent new session establishment, and generate support load and meeting disruption.

Blast radius considerations: CVSS scope is Unchanged (S:U), meaning the impact is expected to remain within the affected security authority, but a signaling outage can propagate operationally to dependent services (session border controllers, conference bridges, recording, and UC integrations) that rely on the affected component. The AV:N/PR:N/UI:N profile means the exposure scales with how widely the signaling interface is reachable — internet-exposed deployments carry materially higher risk than internally segmented ones.

The CVSS base score is 7.5 (HIGH), driven entirely by A:H, with C:N/I:N. This is a pure denial-of-service profile: no data exposure, no tampering vector. CISA KEV status is NO, and no exploit code, PoC, or Nuclei template is known, which lowers near-term opportunistic risk — but the low attack complexity means the barrier to weaponization is low once the triggering input is characterized.

Detection Guidance

Sigma Rule

title: Pexip Infinity Signaling Crash - Repeated Abort / Process Restart
id: 8f3c1a92-4d5e-4b77-9a10-cve2026103100
status: experimental
description: Detects anomalous signaling-service termination or repeated restarts consistent with CVE-2026-103100 denial-of-service aborts on Pexip Infinity before 40.1.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-103100
author: valtersit.com
date: 2026/01/01
logsource:
  category: application
  product: pexip
detection:
  selection_abort:
    EventID|contains:
      - 'abort'
      - 'assert'
      - 'signal'
    Message|contains:
      - 'aborted'
      - 'signal handler'
      - 'unexpected signal'
  selection_restart:
    Message|contains:
      - 'service restart'
      - 'process exited unexpectedly'
      - 'core dumped'
  condition: selection_abort or selection_restart
falsepositives:
  - Planned service restarts or maintenance windows
  - Legitimate malformed client traffic during fuzzing/testing
level: medium
tags:
  - attack.t1499
  - cve.2026.103100

YARA Rule

rule CVE_2026_103100_Pexip_Infinity_Signaling_DoS
{
    meta:
        description = "Detects artifacts referencing Pexip Infinity signaling abort condition associated with CVE-2026-103100"
        author = "valtersit.com"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-103100"
        date = "2026-01-01"
        severity = "high"

    strings:
        $a = "Pexip Infinity" ascii nocase
        $b = "signaling" ascii nocase
        $c = "abort" ascii nocase
        $d = "assert" ascii nocase

    condition:
        uint16(0) == 0x5A4D and
        $a and ($b and ($c or $d))
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2026-103100 Pexip Infinity Signaling Input Validation DoS Attempt"; flow:to_server,established; content:"Pexip"; nocase; classtype:attempted-dos; reference:cve,2026-103100; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-103100; sid:2026103100; rev:1;)

Elastic Detection

sequence by process.name with maxspan=30s
  [process where process.name : "pexip*" and event.action == "terminated"]
  [process where process.name : "pexip*" and event.action == "started"]

Splunk SPL Query

index=application sourcetype=pexip* 
| search ("abort" OR "assert" OR "core dumped" OR "process exited unexpectedly" OR "signal handler")
| stats count min(_time) as first_seen max(_time) as last_seen by host, process, message
| where count > 2
| eval severity=if(count>10,"HIGH","MEDIUM")
| table first_seen, last_seen, host, process, count, severity, message
| sort - count

Wazuh OSSEC Rule

<group name="pexip,cve-2026-103100,">
  <rule id="103100" level="10">
    <decoded_as>json</decoded_as>
    <field name="source">pexip</field>
    <match>abort|assert|signal handler|core dumped|process exited unexpectedly</match>
    <description>CVE-2026-103100 - Pexip Infinity signaling abort or abnormal termination detected</description>
    <mitre>
      <id>T1499</id>
    </mitre>
    <group>denial_of_service,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source).

1. Immediate mitigations.

• Isolate the signaling interface: restrict network access to Pexip Infinity signaling ports using firewall rules, ACLs, and security groups so that only trusted peers and expected geographic/network ranges can reach them.
• Reduce public exposure: for deployments that allow external participants, terminate untrusted signaling at a hardened, monitored ingress component and avoid direct internet exposure of management or internal signaling interfaces.
• Rate limiting and connection controls: apply connection-rate and message-rate limits at perimeter devices to constrain an attacker's ability to repeatedly trigger the abort.
• Monitor and auto-restart: ensure the affected signaling component is supervised with health checks and automatic restart so any abort produces a minimal outage window.
• Enable verbose logging for signaling errors and process termination events so abort triggers can be characterized.

2. Patch/upgrade steps.

• Upgrade Pexip Infinity to version 40.1 or later, the version line in which the vulnerability is remediated per the NVD description ("before 40.1"). Validate the target version on all nodes and conferencing components, not only the primary management node.
• Because no patch source or vendor advisory text was provided in this dataset, treat 40.1 as the minimum fixed version and confirm against the vendor's official release notes before scheduling change windows.
• Roll out to staging First, verify signaling interoperability with integrated UC and SBC platforms, then phase production upgrades to avoid conferencing outages.

3. Long-term hardening.

• Adopt a routine patch cadence that tracks Pexip release notes; the vulnerability is version-gated and therefore fully avoidable on current releases.
• Reduce the internet-facing signaling footprint where feasible (network segmentation, zero-trust ingress, allow-listing of peer signaling infrastructure).
• Track CVSS-based SLAs: with a 7.5 HIGH availability-only score, prioritize internet-exposed and mission-critical conferencing clusters over isolated internal deployments.
• Maintain detections for process abort/restart churn (see Sigma/Elastic/Splunk/Wazuh above) as an early warning for either this CVE or future signaling DoS defects, since CWE-617 patterns recur in protocol-facing parsers.
• Subscribe to CISA KEV and vendor advisories in case exploitation status changes; currently KEV status is NO and no public exploit has been observed.

References

• NVD — CVE-2026-103100: https://nvd.nist.gov/vuln/detail/CVE-2026-103100
• CWE-617 — Reachable Assertion: https://cwe.mitre.org/data/definitions/617.html
• MITRE ATT&CK T1499 — Endpoint Denial of Service: https://attack.mitre.org/techniques/T1499/
• FIRST EPSS (not yet scored for this CVE at time of writing): https://www.first.org/epss/
• Pexip Infinity release notes / 40.1 upgrade documentation: consult the official Pexip product documentation portal for the authoritative fix confirmation.

Exploit-in-the-wild evidence: none reported. No threat actor campaign attribution available. CISA KEV: not listed.