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

Description

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.

Timeline

Scores

EPSS (exploitation in 30 days)

1.1% · top 33% of all CVEs (14 Nov 2026)

CISA SSVC

Exploitation: poc · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Affected products

• libsoup

  • affected ≤ 3.6.5

• Red Hat · Red Hat Enterprise Linux 10

  • unaffected 0:3.6.5-3.el10_0.6 – < *

• Red Hat · Red Hat Enterprise Linux 7 Extended Lifecycle Support

  • unaffected 0:2.62.2-9.el7_9 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:2.62.3-9.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8

  • unaffected 0:2.62.3-9.el8_10 – < *

• Red Hat · Red Hat Enterprise Linux 8.2 Advanced Update Support

  • unaffected 0:2.62.3-1.el8_2.5 – < *

• Red Hat · Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

  • unaffected 0:2.62.3-2.el8_4.5 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

  • unaffected 0:2.62.3-2.el8_6.5 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Telecommunications Update Service

  • unaffected 0:2.62.3-2.el8_6.5 – < *

• Red Hat · Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions

  • unaffected 0:2.62.3-2.el8_6.5 – < *

• Red Hat · Red Hat Enterprise Linux 8.8 Extended Update Support

  • unaffected 0:2.62.3-3.el8_8.5 – < *

• Red Hat · Red Hat Enterprise Linux 9

  • unaffected 0:2.72.0-10.el9_6.2 – < *

• Red Hat · Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

  • unaffected 0:2.72.0-8.el9_0.5 – < *

• Red Hat · Red Hat Enterprise Linux 9.2 Extended Update Support

  • unaffected 0:2.72.0-8.el9_2.5 – < *

• Red Hat · Red Hat Enterprise Linux 9.4 Extended Update Support

  • unaffected 0:2.72.0-8.el9_4.5 – < *

• Red Hat · Red Hat Enterprise Linux 6

  All versions: unknown

What to do

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.

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2025-15741 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-4948](https://cveledger.app/badge/CVE-2025-4948.svg)](https://cveledger.app/cve/CVE-2025-4948)

Record last updated 4 Nov 2026, 21:35 UTC.