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CVE Record

CVE-2026-5119: Libsoup: libsoup: information disclosure via cleartext transmission of cookies during https tunnel establishment

A flaw was found in libsoup. When establishing HTTPS tunnels through a configured HTTP proxy, sensitive session cookies are transmitted in cleartext within the initial HTTP CONNECT request. A network-positioned attacker or a malicious HTTP proxy can intercept these cookies, leading to potential session hijacking or user impersonation.

MediumCVSS 5.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-5119 can expose session cookies when a libsoup-based application connects to HTTPS through an HTTP proxy. The cookies may be sent in cleartext during tunnel setup, letting a malicious proxy or network-positioned attacker steal sessions. The issue is medium severity but important where proxying and authenticated applications overlap.

Executive priority

Treat this as targeted remediation, not an emergency. Patch affected proxy-using RHEL systems promptly, especially where session cookies protect business applications or privileged workflows.

Technical view

libsoup and libsoup3 may include sensitive cookies in the initial HTTP CONNECT request used to establish an HTTPS tunnel through a configured HTTP proxy. Because CONNECT setup is cleartext to the proxy, cookies can be disclosed before TLS protects the target connection. Red Hat lists affected RHEL streams and package builds for libsoup/libsoup3.

Likely exposure

Exposure is most likely on affected Red Hat Enterprise Linux systems running applications that use libsoup or libsoup3, authenticate with cookies, and route HTTPS traffic through configured HTTP proxies.

Exploitation context

The bundle does not show CISA KEV listing or confirmed active exploitation. Practical abuse requires a malicious proxy or suitable network position and a victim workflow that sends relevant cookies through libsoup during HTTPS tunnel establishment.

Researcher notes

Key validation is whether cookies are attached to CONNECT requests in affected builds and whether an HTTP proxy can observe them. The source bundle supports disclosure and potential hijacking impact, but not active exploitation or broad product claims beyond listed Red Hat packages.

Mitigation direction

  • Apply the relevant Red Hat security advisory updates for affected RHEL streams.
  • Prioritize systems using HTTP proxies with authenticated libsoup-based applications.
  • Avoid untrusted HTTP proxies for sensitive application traffic where operationally possible.
  • Review Red Hat guidance for RHEL 6, which is listed with unknown status.
  • Consider session rotation where exposed proxy paths handled sensitive authenticated traffic.

Validation and detection

  • Inventory installed libsoup and libsoup3 packages across RHEL systems.
  • Compare package versions and streams against Red Hat CVE and RHSA records.
  • Identify applications using libsoup with configured HTTP proxies.
  • Confirm updated packages match the applicable Red Hat advisory state.
  • Review proxy architecture for paths carrying authenticated application traffic.
Prepared
Confidence
high
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-319: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2026-5119 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.9 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
5Timeline events
1ADP providers
18Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.9CVSS 3.1MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N1.64.2redhat

Vulnerability scoring details

Base CVSS 3.1 score

5.9Medium
CVSS 3.1 vector shape for CVE-2026-5119Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. Source timelineredhat

    Reported to Red Hat.

  3. Source timelineredhat

    Made public.

  4. CVE publishedCVE Program

    The CVE record was published.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
Red HatRed Hat Enterprise Linux 10libsoup3, 0:3.6.5-3.el10_1.11affected
Red HatRed Hat Enterprise Linux 10libsoup3, 0:3.6.5-3.el10_2.11affected
Red HatRed Hat Enterprise Linux 10.0 Extended Update Supportlibsoup3, 0:3.6.5-3.el10_0.15affected
Red HatRed Hat Enterprise Linux 7 Extended Lifecycle Supportlibsoup, 0:2.62.2-12.el7_9affected
Red HatRed Hat Enterprise Linux 8libsoup, 0:2.62.3-14.el8_10affected
Red HatRed Hat Enterprise Linux 8libsoup, 0:2.62.3-14.el8_10affected
Red HatRed Hat Enterprise Linux 8.4 Advanced Mission Critical Update Supportlibsoup, 0:2.62.3-2.el8_4.9affected
Red HatRed Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-Onlibsoup, 0:2.62.3-2.el8_4.9affected
Red HatRed Hat Enterprise Linux 8.6 Advanced Mission Critical Update Supportlibsoup, 0:2.62.3-2.el8_6.9affected
Red HatRed Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-Onlibsoup, 0:2.62.3-2.el8_6.9affected
Red HatRed Hat Enterprise Linux 8.8 Telecommunications Update Servicelibsoup, 0:2.62.3-3.el8_8.9affected
Red HatRed Hat Enterprise Linux 8.8 Update Services for SAP Solutionslibsoup, 0:2.62.3-3.el8_8.9affected
Red HatRed Hat Enterprise Linux 9libsoup, 0:2.72.0-12.el9_7.6affected
Red HatRed Hat Enterprise Linux 9libsoup, 0:2.72.0-16.el9_8.1affected
Red HatRed Hat Enterprise Linux 9.0 Update Services for SAP Solutionslibsoup, 0:2.72.0-8.el9_0.10affected
Red HatRed Hat Enterprise Linux 9.2 Update Services for SAP Solutionslibsoup, 0:2.72.0-8.el9_2.11affected
Red HatRed Hat Enterprise Linux 9.4 Update Services for SAP Solutionslibsoup, 0:2.72.0-8.el9_4.10affected
Red HatRed Hat Enterprise Linux 9.6 Extended Update Supportlibsoup, 0:2.72.0-10.el9_6.7affected
Red HatRed Hat Enterprise Linux 6libsoupunknown
Weakness

CWE details

CWE-319

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-319 · source CWE mapping

Cleartext Transmission of Sensitive Information

Cleartext Transmission of Sensitive Information represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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