50/100 CVSS 7.7 🔴 CVE ANALYSISPublished: June 30, 2026

Fission: Cross-namespace Environment reference in Package allows build-time command execution and SA token exfiltration

### Summary Fission's `buildermgr` controller processed `Package` CRDs without verifying that `Package.spec.environment.namespace` matched `Package.metadata.namespace`. ### Details An attacker with `packages.fission.io/create` in their own namespace could set `spec.environment.namespace` to any other tenant's namespace. The controller then used its...

7.7

CVSS Score

MEDIUM

Threat Level

Priority /100

TBD

Exploited ITW

Monitor

CISA Status

Sources

🔵

HIGH-PRIORITY SECURITY ADVISORY — Priority Score: 50/100

CVSS 7.7 MEDIUM. SENTINEL APEX recommends immediate patch evaluation. Intelligence from 1 confirmed source(s).

📋 Executive Summary

⚡ Analyst Assessment — SENTINEL APEX v4.0

CYBERDUDEBIVASH SENTINEL APEX has confirmed a MEDIUM-tier threat intelligence signal for CVE-2026-49821 affecting go github.com/fission/fission. Composite threat score: 50/100. Intelligence corroborated across 1 source(s): github_advisories. CVSS base score: 7.7. Exploitation probability assessed as HIGH based on vulnerability characteristics.

Intelligence sources: github_advisories

⚠️ Business Impact Analysis

⚠️ Privilege escalation — local attacker can become SYSTEM/root
⚠️ Data exfiltration risk — customer and sensitive data at risk

🔗 Attack Chain Analysis

Step-by-step attack chain based on observed TTPs and vulnerability characteristics:

#	Phase	Attacker Action	MITRE
1	Reconnaissance	Attacker identifies exposed github.com/fission/fission instances via Shodan, Censys, or targeted scanning	`TA0043`
2	Initial Access	Exploitation of CVE-2026-49821 in go github.com/fission/fission	`T1190`
3	Privilege Escalation	Local privilege escalation to SYSTEM/root for full control	`T1068`
4	Persistence	Backdoor, scheduled task, or new admin account created for persistent access	`T1053`
5	Command & Control	Attacker establishes persistent C2 channel using HTTPS or DNS tunneling	`T1071`
6	Impact / Objectives	Intellectual property theft, espionage, cryptomining, or preparation for future attack stage	`T1657`

⚠ Deep Dive Analysis

This high-severity vulnerability in go github.com/fission/fission (CVSS 7.7) represents a significant attack surface. SENTINEL APEX assesses exploitation to be technically feasible with moderate effort. Organizations running github.com/fission/fission in internet-facing or privileged positions face immediate risk.

SENTINEL APEX URGENCY: ELEVATED. Score: 50/100 MEDIUM. Patch before exploitation activity begins.

🎯 MITRE ATT&CK Mapping

Category	Mapping
Primary Tactic	ML Attack Staging
Primary Technique	AML.T0040 — ML Attack Staging
Sub-Technique	AML.T0000 — AI/ML System Enumeration
Weakness (CWE)	CWE-441
Intel Type	🔴 CVE ANALYSIS
Source(s)	github_advisories

🔴 CVE Reference

CVE ID	Reference	Score
CVE-2026-49821	NVD →	7.7
CVE-2026-49821	NVD →	7.7

🏷️ Indicators of Compromise — Enriched IOC Feed

Normalized IOCs with confidence scoring. Block immediately across all enforcement points. SOC Pro subscribers receive enriched IOC bundles with full attribution and STIX/TAXII feeds.

Indicator Value	Type	Confidence	First Seen
packages.fission.io	domain	75%	2026-06-30

🔍 Detection Rules — Sigma (SIEM)

Deploy to Splunk, Elastic, Microsoft Sentinel, or QRadar. SOC Pro subscribers receive pre-compiled SIEM-native query packs updated with each pipeline run.

Sigma YAMLtitle: CVE-2026-49821 Exploitation Attempt — go github.com/fission/fission
id: d555a925773335a2-43b1
status: experimental
description: Detects exploitation of CVE-2026-49821 in go github.com/fission/fission. Priority: MEDIUM. Score: 50/100
author: CYBERDUDEBIVASH SENTINEL APEX v4.0 (bivash@cyberdudebivash.com)
date: 2026-06-30
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2026-49821
    - https://blog.cyberdudebivash.in/
tags:
    - attack.initial_access
    - attack.t1190
    - cve-2026-49821
    - cve-2026-49821
logsource:
    category: webserver
detection:
    keywords:
        - 'CVE-2026-49821'
        - 'CVE-2026-49821'
        - 'cve-2026-49821'
    condition: keywords
falsepositives:
    - Security scanners
level: medium

📡 Detection Rules — YARA (Endpoint)

Deploy to endpoint detection platforms. Enterprise subscribers receive tuned, FP-validated YARA rule packs.

YARArule CVE_2026_49821_Exploitation {
    meta:
        description = "Detects artifacts related to CVE-2026-49821 exploitation in go github.com/fission/fission"
        author      = "CYBERDUDEBIVASH SENTINEL APEX v4.0"
        date        = "2026-06-30"
        severity    = "HIGH"
        cvss        = "7.7"
        priority    = "50/100"
        threat_level = "MEDIUM"
        reference   = "https://nvd.nist.gov/vuln/detail/CVE-2026-49821"
    strings:
        $id_str  = "CVE-2026-49821" ascii nocase
        $product = "github_com_fission_fission" ascii nocase wide
    condition:
        any of them
}

🛡️ SOC Response Playbook

1IMMEDIATE (0-1hr): Identify all instances of github.com/fission/fission in your environment via CMDB/asset inventory
2IMMEDIATE: Block all 1 IOCs in this report at firewall, proxy, DNS, and EDR simultaneously
3IMMEDIATE (0-1hr): Apply vendor patch — no maintenance window exception for MEDIUM threats
4IMMEDIATE (1-2hr): If no patch available: implement WAF rules, ACLs, or network-level compensating controls
5SHORT-TERM (2-4hr): Deploy Sigma detection rule to SIEM — validate alert generation in test environment
6SHORT-TERM (4-8hr): Review logs for exploitation indicators (anomalous github.com/fission/fission requests, error spikes)
7SHORT-TERM (8-24hr): Hunt for post-exploitation: new admin accounts, scheduled tasks, lateral movement
8MONITOR: Subscribe to go security advisories for patch updates
9ONGOING: Track SENTINEL APEX intelligence feed for follow-on campaigns targeting github.com/fission/fission

📎 Intelligence References

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⚡ CYBERDUDEBIVASH SENTINEL APEX v4.0

Intelligence report generated by CYBERDUDEBIVASH SENTINEL APEX v4.0
Report ID: SENTINEL-CVE-2026-49821-2026-06-30 | Priority: 50/100 MEDIUM | Sources: 1
© 2026 CYBERDUDEBIVASH PRIVATE LIMITED
Republication requires written attribution to CYBERDUDEBIVASH SENTINEL APEX

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