CVE-2026-12549Public exploitNetwork attack vector

Response corruption via unclamped Range suffix start

Published Jun 22, 2026 · Updated Jun 22, 2026

Improper length handling in libsoup on Red Hat Enterprise Linux 8, 9, and 10 allows remote attackers to cause malformed HTTP 206 responses. SoupServer computes a negative range start when a suffix length exceeds the content size, then fails to clamp that value after a signed-comparison rework. An unauthenticated client must reach an application using libsoup's server-side Range handling; the result is malformed partial content and log flooding.

CVSS severity4.8
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper length handling in libsoup on Red Hat Enterprise Linux 8, 9, and 10 allows remote attackers to cause malformed HTTP 206 responses. SoupServer computes a negative range start when a suffix length exceeds the content size, then fails to clamp that value after a signed-comparison rework. An unauthenticated client must reach an application using libsoup's server-side Range handling; the result is malformed partial content and log flooding.

The record

CVE
CVE-2026-12549
Published
Jun 22, 2026
Updated
Jun 22, 2026
Vendor
389 Directory Server
Product
Red Hat Enterprise Linux 10
Classifications
CWE-805, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 22, 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 Enterprise Linux 10Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 9Affected versions are unavailable in this record.
389 Directory Server · Red Hat Enterprise Linux 8Affected versions are unavailable in this record.

Published CVSS scores

4.8Red HatCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

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 exploitPublished

Weakness, pattern, technique

CWE-805Buffer Access with Incorrect Length Value
T1190Exploit Public-Facing Application

Public exploit references

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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