CVE-2026-49329Network attack vector

Authentication denial via underscore separator parsing bypass

Published Sep 1, 2026 · Updated Sep 1, 2026

Denial of service in Red Hat OpenShift Container Platform 4 allows remote attackers to block cluster authentication via a crafted header. OAuth login and error handlers pass Accept-Language to ParseAcceptLanguage after a guard counts hyphens but not underscores, which the BCP 47 scanner treats as hyphens and parses quadratically. Unauthenticated access to either endpoint is sufficient; CPU exhaustion denies authentication to all cluster users.

CVSS severity7.5
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Red Hat OpenShift Container Platform 4 allows remote attackers to block cluster authentication via a crafted header. OAuth login and error handlers pass Accept-Language to ParseAcceptLanguage after a guard counts hyphens but not underscores, which the BCP 47 scanner treats as hyphens and parses quadratically. Unauthenticated access to either endpoint is sufficient; CPU exhaustion denies authentication to all cluster users.

The record

CVE
CVE-2026-49329
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
389 Directory Server
Product
Red Hat OpenShift Container Platform 4
Classifications
CWE-407, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

389 Directory Server · Red Hat OpenShift Container Platform 4Affected versions are unavailable in this record.

Published CVSS scores

7.5Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

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

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-407Inefficient Algorithmic Complexity
T1499Endpoint Denial of Service

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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