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CVE-2026-48558

CRITICAL 9.5 KNOWN EXPLOITED PoC CATALOGUED DETECTION TEMPLATE ALL-YEARS

Published 2026-06-12 · Last modified 2026-10-07 · VulnCheck · NVD: Analyzed

SimpleHelp versions 5.5.15 and prior and 6.0 pre-release versions contain an authentication bypass vulnerability in the OIDC authentication flow. When OIDC authentication is configured, identity tokens submitted during login are accepted without verifying their cryptographic signature. In a vulnerable configuration, a remote, unauthenticated attacker can submit a forged token containing arbitrary identity claims to obtain a fully authenticated technician session. In some configurations, this may also allow bypass of multi-factor authentication. No user interaction is required.

ACTIVELY EXPLOITED

Confirmed exploited in the wild — in CISA KEV since 2026-06-29. Patch or mitigate now.

Exploitation likelihood

77.7%chance of exploitation in 30 days · 100th percentile

● In CISA KEV (2026-06-29)● Catalogued PoC◆ SSVC: exploitation active, automatable yes

Impact if exploited

9.5CVSS 4.0 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable
  • ⚠Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

Public PoC or exploit resources are catalogued below.

Listed by the named source; Vulnpedia has not tested these resources.

PoC data: JSON

Detection templates

Detection checks are listed separately from PoCs.

Resource commands

nuclei -id CVE-2026-48558 -u https://TARGETDetection template — review its checks and affected versions before use.
curl -s https://vulnpedia.com/cve/CVE-2026-48558/poc.jsonMachine-readable PoC index for this CVE (for automation).

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Simplehelp Simple Help

Products Simplehelp

Weakness (CWE)

  • CWE-347: Improper Verification of Cryptographic Signature

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References and research data (JSON)

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

1 candidate

Additional exploitation reports

Source-specific reports, separate from CISA KEV. Repeated observations from one source are not independent confirmations.

  • VulnCheck KEV · 2026-06-29T00:00:00Z

    Source guidance: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

    Source ransomware assessment: Unknown

    VulnCheck KEV · CVE-2026-48558 · Updated 2026-06-29T00:00:00Z
  • VulnCheck KEV · 2026-06-29T00:00:00ZVulnCheck KEV · CVE-2026-48558
    VulnCheck KEV · CVE-2026-48558
    VulnCheck KEV · CVE-2026-48558
  • VulnCheck KEV · 2026-07-10T00:00:00ZVulnCheck KEV · CVE-2026-48558
  • VulnCheck KEV · 2026-07-27T00:00:00ZVulnCheck KEV · CVE-2026-48558
  • VulnCheck KEV · 2026-08-05T00:00:00ZVulnCheck KEV · CVE-2026-48558
  • VulnCheck KEV · 2026-09-10T00:00:00ZVulnCheck KEV · CVE-2026-48558

Known Affected Software Configurations

VendorProductVersion range
Simple HelpSimplehelp< 5.5.16
Simple HelpSimplehelp6.0

All CVSS metrics

  • CRITICAL 9.5 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
  • CRITICAL 10 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
  • CRITICAL 9.5 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • CRITICAL 10 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

References

Exploit-tagged references (not proof of a PoC)

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS