CVE-2026-76472

Executive Summary

CVE-2026-76472 is a Cisco-tracked identifier covering internally discovered injection-class defects grouped under the CWE-74 ("Injection") pillar, announced as part of a Cisco networking engineering proactive security and product quality review. The advisory text is generic and does not name a specific product, component, interface, or fixed release, so affected scope must be determined from Cisco's own hardening bulletins rather than from this description. With a CVSS 3.1 base score of 8.8 (AV:L / AC:L / PR:L / UI:N / S:C / C:H / I:H / A:H), the impact model is full compromise of confidentiality, integrity, and availability where an authenticated local actor can influence a downstream component, with the scope change indicating that the compromised component can impact resources beyond its original security authority.

Technical Analysis

CVE-2026-76472 is a CVE-root identifier that Cisco describes as "tracked by CVE-76472" and related to "improper neutralization of special elements" grouped under CWE Pillar CWE-74. CWE-74 is the parent pillar for injection weaknesses — it describes a class-level failure rather than a single atomic defect, meaning the underlying issues are injection flaws in which attacker-controlled input is not neutralized for a special element before being used by a downstream component. Because CWE-74 is a pillar, the concrete child weaknesses (for example SQL, OS command, argument/parameter, expression, or template injection) are not enumerated in the supplied text, and any attempt to name them would be speculation.

What the record does establish is the security-relevant shape of the flaw:

• Attack vector (AV:L): The base vector is Local, not Network. The attack is not achieved by sending a single crafted packet from an unauthenticated remote host; it requires some form of local access or a locally reachable interface to the affected software. In an appliance or embedded networking context this typically corresponds to a management shell, CLI, or a locally exposed API/socket rather than a public data plane interface.
• Privileges required (PR:L): The attacker must hold low-level privileges. This is not a pre-auth or unauthenticated issue. An attacker who already holds a restricted account, session, or limited execution context is the relevant threat model.
• User interaction (UI:N): No victim must click or confirm anything; exploitation is programmatic once the precondition of local low-privileged access exists.
• Scope (S:C): The security authority boundary is crossed. Compromise of the vulnerable component affects resources beyond it — consistent with an injection flaw where crafted input is consumed by a downstream component with different (broader) privileges or a different trust boundary.
• C/I/A (H/H/H): Full loss of confidentiality, integrity, and availability is the modeled outcome.

Because the record does not disclose the affected product, the interface through which input is supplied, the downstream consumer of that input, or the specific special elements that fail neutralization, no code-level mechanism can be described without fabrication. The honest characterization is: an injection-class weakness (CWE-74 family) in Cisco software, locally triggerable by a low-privileged actor, escalating across a scope boundary to full compromise of the affected system.

The CVSS vector itself is internally consistent with a post-auth local injection that reaches a privileged downstream subsystem. The scope-change combined with H/H/H subscores is the strongest signal available: this is not a nuisance-level input validation bug — the modeled worst case is complete control of the affected component and the resources it can reach.

Exploitation Scenarios

No public PoC, exploit code, or Nuclei template exists for this CVE, and no in-the-wild exploitation is known. The following chain is inferred strictly from the vulnerability class (CWE-74 injection), the CVSS vector environment, and the vendor language. It deliberately avoids naming any interface, binary, parameter, endpoint, or library not present in the supplied data.

1. Reconnaissance and target identification. The attacker must first identify Cisco systems in scope that correspond to the hardening releases referenced by the advisory. Because no affected product list is published in the record, identification depends on correlating deployed Cisco software versions against Cisco's own security advisory mapping for the CVE root identifier. Network-facing discovery (fingerprinting management interfaces, banners, and TLS certificate subjects) narrows candidates; characterization of the local management or execution surface determines whether the AV:L precondition is reachable.

2. Precondition fulfillment — obtain local low-privileged access. Per AV:L/PR:L, the attacker must already have some local presence: a low-privileged account, an unprivileged local session, or access to a locally reachable interface that feeds input into a component which itself consumes that input in a downstream privileged operation. This precondition is what separates CVE-2026-76472 from an unauthenticated remote exploit — the attacker is an insider, a compromised low-privilege account holder, or someone who has chained a prior foothold.

3. Triggering the injection class. The attacker supplies crafted input containing special elements that the vulnerable component fails to neutralize. In CWE-74-class flaws the damage occurs not at the point of input but at the point of downstream interpretation: the receiving component treats part of the attacker's data as instructions, metacharacters, delimiters, or arguments rather than as inert data. The exact special elements (quoting characters, command separators, query syntax, template delimiters, path or argument separators) are not disclosed in the record and are intentionally not guessed here. The interaction is programmatic and requires no victim action (UI:N).

4. Scope-crossing and post-exploitation impact. Successful neutralization failure allows the injected content to be interpreted by a more privileged downstream component, crossing the security authority boundary modeled by S:C. Because the vector models C:H/I:H/A:H, the realistic post-exploitation outcome is full read of sensitive data on the affected system, modification of configuration or data with integrity implications, and disruption of availability. For a network platform, the blast radius commonly extends to adjacent systems that trust the affected component for routing, policy, authentication, or management. Persistence, credential harvesting, and lateral movement toward the management plane are plausible follow-on actions but are not specified by the advisory.

Confidence statement: This chain is a class-level inference. No step beyond the CVSS vector preconditions (local, low-privileged, no user interaction) and the CWE-74 classification is directly evidenced. No public PoC exists.

Impact Assessment

Business impact is driven by what the affected Cisco component controls. Using the CVSS subscores:

• Attack Vector — Local (AV:L): Reduces the remote-unauthenticated attack surface but elevates insider risk. In a networking environment, local access frequently means management shell, console, or an internal API reachable from an already-compromised host. The practical exposure is therefore "post-foothold escalation and management-plane compromise" rather than opportunistic internet scanning.
• Privileges Required — Low (PR:L): Any holder of a limited account — including contractors, monitoring integrations, or a compromised service identity — is a candidate attacker. This expands the insider threat model materially compared with PR:H issues.
• Scope — Changed (S:C): The most consequential subscore. Compromise is not contained to the vulnerable component; the attacker can reach resources the component itself can reach. On a network device this is the classic path from a confined component to the control plane.
• Confidentiality / Integrity / Availability — High (High): Full loss on all three axes. Traffic and configuration confidentiality loss, configuration and behavior integrity loss, and total availability loss (including denial of service as a byproduct of tampering).

Blast radius: Affected systems are any Cisco deployments corresponding to the hardening releases the advisory describes as addressing these internally discovered issues — the record does not enumerate them, so inventory must be reconciled against Cisco's published advisory mapping. Downstream, systems that trust the affected device (routing peers, AAA infrastructure, management platforms, tenants behind the device) inherit risk via the scope-change. Business consequences include potential network-level outages, configuration tampering with compliance ramifications, exfiltration of control-plane and management credentials, and, in regulated environments, reportable integrity and confidentiality breaches.

Exploitability caveat: EPSS has not been scored by FIRST.org, no CISA KEV listing exists, and no public exploit or PoC is available. Current real-world exploitation risk is therefore assessed as latent rather than imminent — but the severity (8.8) and the scope-change mean it should not be deprioritized for internet-adjacent or internally reachable Cisco infrastructure.

Detection Guidance

Detection for an injection-class flaw is inherently behavioral. Because no specific interface, parameter, or payload syntax is disclosed, the rules below target the generic signatures of CWE-74-class abuse on Cisco-adjacent systems: injection metacharacters in local management activity, process lineage consistent with a low-privileged process invoking a more privileged downstream consumer, and anomalous management-protocol traffic. Tuning is required.

Sigma Rule

title: Potential CWE-74 Injection Abuse on Cisco Systems (CVE-2026-76472)
id: 8f3c1a72-4b6e-4c9a-9d21-76472cve2026
status: experimental
description: Detects locally originated process activity consistent with injection of
  special elements into a downstream privileged component on Cisco software affected
  by CVE-2026-76472 (CWE-74). Class-level heuristic; tune to your environment.
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-76472
author: valtersit.com Threat Intelligence
date: 2026/01/01
logsource:
  category: process_creation
  product: linux
detection:
  selection_injection_metachars:
    CommandLine|contains:
      - ';'
      - '|'
      - '`'
      - '$(('
      - '../'
      - '%00'
  selection_privileged_parent:
    ParentImage|endswith:
      - '/cisco'
      - '/confd'
      - '/cli'
  selection_low_priv_spawn:
    User|startswith:
      - 'guest'
      - 'operator'
      - 'readonly'
  condition: selection_injection_metachars and (selection_privileged_parent or selection_low_priv_spawn)
falsepositives:
  - Legitimate administrative scripts that use shell metacharacters
  - Vendor maintenance tooling invoked during upgrades
level: high
tags:
  - attack.t1190
  - cve.2026.76472
  - cwe.74

YARA Rule

rule CVE_2026_76472_CWE74_Injection_Artifacts
{
    meta:
        description = "Detects artifacts consistent with CWE-74 injection abuse against Cisco software tracked by CVE-2026-76472"
        author = "valtersit.com Threat Intelligence"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2026-76472"
        date = "2026-01-01"
        severity = "high"
        tlp = "WHITE"

    strings:
        $cve = "CVE-2026-76472" ascii wide nocase
        $cwep = "CWE-74" ascii wide nocase
        $inj1 = "';" ascii
        $inj2 = "|" ascii
        $inj3 = "$(" ascii
        $inj4 = "`" ascii
        $inj5 = "${" ascii
        $rce1 = "/bin/sh -c" ascii
        $rce2 = "/bin/bash -c" ascii

    condition:
        uint16(0) != 0x5A4D and
        (
            ($cve and any of ($inj*)) or
            ($cwep and any of ($rce*) and any of ($inj*))
        )
}

Suricata IDS Rule

alert tcp $HOME_NET any -> $HOME_NET [443,22,830] ( \
  msg:"CVE-2026-76472 Possible CWE-74 Injection in Cisco Management Traffic"; \
  flow:established,to_server; \
  content:"CVE-2026-76472"; nocase; \
  content:"$("; distance:0; within:128; nocase; \
  content:"|3B|"; distance:0; within:128; \
  classtype:attempted-admin; \
  sid:202676472; rev:1; \
  metadata:cve CVE-2026-76472, cwe CWE-74; \
  reference:url,nvd.nist.gov/vuln/detail/CVE-2026-76472; )

Note: this rule is a placeholder signature for the CVE identifier and generic injection metacharacters in management-plane traffic. Because no wire-observable payload syntax is disclosed by the advisory, this rule will require significant tuning and should be treated as a hunt aid rather than a production detection.

Elastic Detection

sequence by process.entity_id with maxspan=5s
  [process where process.parent.name : ("cisco", "confd", "cli", "mgmt") and
     process.args : ("*;*", "*|*", "*$(*", "*`*")]
  [process where event.action == "start" and
     user.name : ("root", "admin", "privileged") and
     process.name : ("sh", "bash", "python", "perl")]

Splunk SPL Query

index=os sourcetype=process:* OR sourcetype=sysmon
| eval cve="CVE-2026-76472"
| where (match(CommandLine, ";\s*\w") OR match(CommandLine, "\|") OR match(CommandLine, "\$\(") OR match(CommandLine, "`"))
| search (ParentImage="*cisco*" OR ParentImage="*confd*" OR User IN ("guest","operator","readonly"))
| stats count min(_time) as first_seen max(_time) as last_seen
        values(CommandLine) as commands values(User) as users
        values(ParentImage) as parents by host
| where count > 0
| convert ctime(first_seen) ctime(last_seen)
| table host users parents commands count first_seen last_seen

Wazuh OSSEC Rule

<group name="cisco,cve_2026_76472,injection,">
  <rule id="202676" level="12">
    <decoded_as>json</decoded_as>
    <field name="event.category">process</field>
    <field name="process.parent.name">cisco|confd|cli|mgmt</field>
    <field name="process.command_line" type="pcre2">[;&|`]|\$\(|\$\{</field>
    <description>CVE-2026-76472: Possible CWE-74 injection by low-privileged actor invoking privileged Cisco component</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_76472,</group>
  </rule>

  <rule id="202677" level="15">
    <if_sid>202676</if_sid>
    <field name="user.name">guest|operator|readonly</field>
    <description>CVE-2026-76472: High-confidence injection attempt from low-privileged account</description>
    <mitre>
      <id>T1190</id>
    </mitre>
    <group>cve_2026_76472,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch confidence: 0/4 (UNPATCHED — no patch evidence from any tracked source). No vendor fix version, advisory ID, or workaround is present in the supplied data, and affected version ranges are empty. The vendor statement references "software hardening releases" without mapping them to specific products or versions, so no upgrade target can be named here without fabrication.

1) Immediate mitigations

• Inventory all Cisco systems and reconcile against Cisco's published advisory mapping for this CVE root identifier; the record does not enumerate products, so the mapping must come from the vendor.
• Enforce least privilege aggressively: because PR:L is the precondition, treat every low-privileged account, service identity, and monitoring integration on Cisco devices as an attack path. Audit for unused, shared, or read-only accounts that can nonetheless reach management surfaces.
• Restrict local and management access to a hardened, monitored out-of-band path. Given AV:L, reducing who and what can reach the local/management surface directly reduces exploitability.
• Monitor the detection rules above for injection metacharacters in management activity and for low-privileged processes spawning privileged downstream consumers.
• Consider segmentation to contain the S:C scope change: limit what any single Cisco device is trusted to reach, and rotate credentials that device holds, so a scope-crossing exploit cannot cascade.

2) Patch / upgrade steps

• No fixed version is identified in this record. When Cisco publishes the advisory-to-CVE mapping and fixed releases, upgrade to the earliest release that explicitly lists this CVE identifier as resolved.
• Because this is an internally discovered hardening class, fixes may be distributed across multiple releases; validate against Cisco's own severity and CVE list rather than assuming a single patch resolves all tracked issues.
• After upgrading, re-verify that previously exposed management interfaces and low-privileged roles behave as expected.

3) Long-term hardening

• Build a standing process to consume Cisco hardening/security advisories directly, since CVE-root aggregation advisories do not always map cleanly to product versions in third-party feeds.
• Apply input-validation and output-encoding defenses architecturally where third-party integrations feed data into Cisco platforms — injection (CWE-74) requires that untrusted data be neutralized before downstream interpretation.
• Maintain network telemetry baselines for management-plane activity so behavioral detections can distinguish normal administration from injection attempts.
• Track EPSS, CISA KEV, and vendor bulletins for this CVE; currently EPSS is unscored, KEV status is NO, and no public exploit exists, so risk posture may change if either signal turns.

References

1. NVD — CVE-2026-76472: https://nvd.nist.gov/vuln/detail/CVE-2026-76472
2. CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component ("Injection"): https://cwe.mitre.org/data/definitions/74.html
3. Cisco Security Advisories and Notices (vendor hardening releases referenced by the advisory): https://sec.cloudapps.cisco.com/security/center/publicationListing.x
4. FIRST.org EPSS (currently unscored for this CVE): https://www.first.org/epss/
5. CISA Known Exploited Vulnerabilities Catalog (CVE-2026-76472 not listed as of this writing): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

No threat actor campaigns or exploit-in-the-wild evidence are associated with CVE-2026-76472 in the supplied data. Exploit availability: none public.