CVE-2026-75878Network attack vector

Authentication bypass via unvalidated SSO header

Published Sep 18, 2026 · Updated Sep 18, 2026

Improper authentication in affected IBM Sterling File Gateway 6.2 builds allows remote attackers to obtain fully authenticated sessions. The SSO authentication path accepts the configured username HTTP header without validating its asserted identity. Exposure requires enabled SSO and a matching external account; no credentials or user interaction are required, and success grants that account's permissions.

CVSS severity9.1
Critical
EPSS probability0.64%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in affected IBM Sterling File Gateway 6.2 builds allows remote attackers to obtain fully authenticated sessions. The SSO authentication path accepts the configured username HTTP header without validating its asserted identity. Exposure requires enabled SSO and a matching external account; no credentials or user interaction are required, and success grants that account's permissions.

The record

CVE
CVE-2026-75878
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
IBM
Product
IBM Sterling File Gateway
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.2.0.0 <=6.2.0.6_1, 6.2.1.0 - 6.2.1.2, 6.2.2.0 - 6.2.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

IBM · IBM Sterling File Gatewayversion=6.2.0.0 <=6.2.0.6_1, 6.2.1.0 - 6.2.1.2, 6.2.2.0 - 6.2.2.1

Published CVSS scores

9.1IBMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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