Out-of-bounds ReadWeakness · CWE-125

CVE-2026-15714

MEDIUM · 6.5 CVSS v3.1 Published 2026-07-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click 5 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An out-of-bounds read vulnerability was found in libsoup's multipart processing subsystem. The flaw exists in the soup_multipart_input_stream_read_headers() function inside soup-multipart-input-stream.c, which does not adequately restrict or validate the size of incoming multipart boundary strings. When processing a crafted HTTP response containing a malformed or oversized boundary parameter, the internal stream reader reads past the allocated buffer bounds. A remote, unauthenticated attacker can exploit this behavior to cause a service denial (DoS) through application failure or potentially read fragments of unauthorized memory metadata.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

An out-of-bounds read vulnerability exists in libsoup's multipart processing within the soup_multipart_input_stream_read_headers() function. The function fails to validate the size of incoming multipart boundary strings, allowing a crafted HTTP response with an oversized boundary parameter to read beyond allocated buffer bounds. A remote, unauthenticated attacker can exploit this to cause denial of service or leak memory fragments.

MitigationUpdate libsoup to the latest version containing the boundary size validation fix. Until a patch is available, implement input validation at the application layer to reject HTTP responses with boundary parameters exceeding expected maximum lengths.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
Low

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if libsoup is installed
    Run 'pkg-config --modversion libsoup-3.0' or 'pkg-config --modversion libsoup-2.4' to check the installed version. On Debian-based systems, also check 'dpkg -l | grep libsoup'.
    Affected if libsoup is present and the version is lower than the patched version containing boundary size validation fix in soup_multipart_input_stream_read_headers().
  2. Determine if multipart HTTP responses are processed
    Inspect application code or runtime behavior to see if it handles multipart/form-data or multipart/related HTTP responses using libsoup's soup_multipart_input_stream API.
    Affected if The application processes multipart HTTP responses through libsoup, enabling the vulnerable code path in soup_multipart_input_stream_read_headers().
  3. Inspect HTTP response handling for boundary parameter usage
    Use network tracing (e.g., Wireshark) or application logs to observe if HTTP responses contain Content-Type headers with multipart boundary parameters.
    Affected if The application receives HTTP responses with multipart boundary parameters, which triggers the vulnerable function without size validation.
  4. Check for crashes or memory anomalies in multipart processing
    Review application logs, crash reports, or memory dumps for indicators of out-of-bounds read errors occurring during multipart header parsing.
    Affected if Crashes or abnormal memory reads occur specifically when processing multipart response headers, indicating the vulnerability may be triggered.

A user is affected if libsoup is installed with an unpatched version that lacks boundary size validation AND the application processes multipart HTTP responses containing boundary parameters.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update libsoup to the latest version containing the boundary size validation fix. Until a patch is available, implement input validation at the application layer to reject HTTP responses with boundary parameters exceeding expected maximum lengths.

Recommended fix Moderate confidence

Fixed libsoup version as specified in distribution security advisory (e.g., RHEL errata)

  1. 1. Identify the exact version of libsoup currently installed in your environment using your system's package manager (e.g., rpm -q libsoup for RHEL/Fedora, dpkg -l libsoup for Debian/Ubuntu).
  2. 2. Check the GNOME GitLab libsoup repository (gitlab.gnome.org/GNOME/libsoup) for commits addressing the boundary validation issue in soup-multipart-input-stream.c.
  3. 3. Consult Red Hat's bugzilla (bugzilla.redhat.com) for CVE-2026-15714 to obtain the specific fixed version for RHEL-based distributions.
  4. 4. Upgrade to the fixed version of libsoup provided by your distribution's security advisories.
Caveat Minor - libsoup patch updates typically do not introduce breaking API changes; however, verify any multipart-related functionality after upgrade.

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-15714 in production — separate from our analysis above.

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What this is

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What belongs here
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