# CVE-2025-4948: Libsoup: integer underflow in soup_multipart_new_from_message() leading to denial of service in libsoup

Status: published. Published: 2025-05-19. Updated: 2026-11-04.

A flaw was found in the soup_multipart_new_from_message() function of the libsoup HTTP library, which is commonly used by GNOME and other applications to handle web communications. The issue occurs when the library processes specially crafted multipart messages. Due to improper validation, an internal calculation can go wrong, leading to an integer underflow. This can cause the program to access invalid memory and crash. As a result, any application or server using libsoup could be forced to exit unexpectedly, creating a denial-of-service (DoS) risk.

## Remediation

- workaround: To mitigate this issue, Red Hat recommends avoiding the use of libsoup with untrusted or unauthenticated multipart HTTP message sources until updated packages are available. Administrators can deploy application-level filters or HTTP proxies that reject malformed multipart requests. It is strongly advised to apply vendor-supplied patches as soon as they are released to address this integer underflow vulnerability and restore the stability of affected services. (source: CNA: redhat)

## Affected products and versions

-  /  (libsoup): ≥ 0; ≤ 3.6.5 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (libsoup3): ≥ 0:3.6.5-3.el10_0.6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 Extended Lifecycle Support (libsoup): ≥ 0:2.62.2-9.el7_9; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (libsoup): ≥ 0:2.62.3-9.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.2 Advanced Update Support (libsoup): ≥ 0:2.62.3-1.el8_2.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (libsoup): ≥ 0:2.62.3-2.el8_4.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (libsoup): ≥ 0:2.62.3-2.el8_6.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (libsoup): ≥ 0:2.62.3-2.el8_6.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (libsoup): ≥ 0:2.62.3-2.el8_6.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Extended Update Support (libsoup): ≥ 0:2.62.3-3.el8_8.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (libsoup): ≥ 0:2.72.0-10.el9_6.2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (libsoup): ≥ 0:2.72.0-8.el9_0.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Extended Update Support (libsoup): ≥ 0:2.72.0-8.el9_2.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (libsoup): ≥ 0:2.72.0-8.el9_4.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (libsoup): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.81% as of 2026-11-04; percentile 57.07%

- SSVC: exploitation poc; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-191

## Exploit evidence

- exploit: https://gitlab.gnome.org/GNOME/libsoup/-/work_items/449 (ADP: CISA-ADP)

## References

- https://access.redhat.com/errata/RHSA-2025:21657 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8126 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8128 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8132 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8139 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8140 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8252 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8480 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8481 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8482 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8663 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2025-4948 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2367183 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://gitlab.gnome.org/GNOME/libsoup/-/issues/449 (CNA: redhat)

- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/449 (ADP: CISA-ADP; exploit)

- https://access.redhat.com/errata/RHSA-2025:21657 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8126 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8128 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8132 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8139 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8140 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8252 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8480 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8481 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8482 (secalert@redhat.com)

- https://access.redhat.com/errata/RHSA-2025:8663 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2025-4948 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2367183 (secalert@redhat.com)

- https://gitlab.gnome.org/GNOME/libsoup/-/issues/449 (secalert@redhat.com)

- https://gitlab.gnome.org/GNOME/libsoup/-/work_items/449 (134c704f-9b21-4f2e-91b3-4a467353bcc0)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-4948; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-4948; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-4948; retrieved 2026-11-04; source updated Not reported

Revision: 1669305e78de61b2be8ffeaf37d863636357303795b6b008f89df581ccd5bb76

Canonical: https://y2.dev/cve/CVE-2025-4948

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