Libsoup: libsoup: http request smuggling via duplicate content-length headers

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Summary

CVECVE-2026-2708
StatePUBLISHED
Assignerredhat
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-23 22:16:29 UTC
Updated2026-05-04 18:28:46 UTC
DescriptionA request smuggling vulnerability exists in libsoup's HTTP/1 header parsing logic. The soup_message_headers_append_common() function in libsoup/soup-message-headers.c unconditionally appends each header value without validating for duplicate or conflicting Content-Length fields. This allows an attacker to send HTTP requests containing multiple Content-Length headers with differing values.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS: 0.000350000 probability, percentile 0.102980000 (date 2026-05-05)

Problem Types: CWE-444 | CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary5.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1[email protected]Secondary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNACVSS3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Gnome Libsoup - All All All
Operating System Redhat Enterprise Linux 10.0 All All All
Operating System Redhat Enterprise Linux 6.0 All All All
Operating System Redhat Enterprise Linux 7.0 All All All
Operating System Redhat Enterprise Linux 8.0 All All All
Operating System Redhat Enterprise Linux 9.0 All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Red Hat Red Hat Enterprise Linux 10 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 6 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 7 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 8 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 9 Not specified Not specified

References

ReferenceSourceLinkTags
access.redhat.com/security/cve/CVE-2026-2708 [email protected] access.redhat.com Vendor Advisory
gitlab.gnome.org/GNOME/libsoup/-/merge_requests/513 [email protected] gitlab.gnome.org Issue Tracking
bugzilla.redhat.com/show_bug.cgi [email protected] bugzilla.redhat.com Issue Tracking, Vendor Advisory
gitlab.gnome.org/GNOME/libsoup/-/issues/500 [email protected] gitlab.gnome.org Exploit, Issue Tracking, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Red Hat would like to thank Cavid for reporting this issue. (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-02-18T19:56:04.948ZReported to Red Hat.
CNA2026-02-18T20:13:57.701ZMade public.
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