Description
A flaw was found in libsoup's WebSocket implementation when using the permessage-deflate extension. The extension's decompression loop (inflate()) processes data in chunks without enforcing an upper boundary limit on the output buffer size. While libsoup limits the incoming compressed frame size via max_incoming_payload_size, it fails to track or limit memory allocation during decompression. A separate check for decompressed size (max_total_message_size) exists but executes only after inflation is complete, and it is entirely disabled by default for client connections. A remote, unauthenticated attacker can exploit this by sending a small, highly compressed payload (a decompression bomb), causing unbounded memory allocation that triggers an Out-of-Memory (OOM) crash and a Denial of Service (DoS).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | — | — |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | — | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | — | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | — | — |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9 | — | — |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | — | — |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | — | — |
| Red Hat | Red Hat Enterprise Linux 6 | — | — |
| Red Hat | Red Hat Enterprise Linux 7 | — | — |
| Red Hat | Red Hat Enterprise Linux 8 | — | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 13 | libsoup3 +1 | No fix yet | — |
| Debian 12 | libsoup3 +1 | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libsoup3 +1 | No fix yet | — |
| Ubuntu 26.04 LTS | libsoup3 | No fix yet | — |
| Ubuntu 24.04 LTS | libsoup3 +1 | No fix yet | — |
| Ubuntu 22.04 LTS | libsoup2.4 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | libsoup2.4 | No fix yet | — |
| Ubuntu Pro 22.04 LTS | libsoup3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | libsoup2.4 | No fix yet | — |
| Ubuntu Pro 18.04 LTS | libsoup2.4 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | libsoup2.4 | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | libsoup3 +2 | 3.6.5-3.el10_2.14 | RHSA-2026:68235 |
| RHEL 9 | libsoup +1 | 2.72.0-16.el9_8.3 | RHSA-2026:68234 |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10.0 EUS | libsoup3 +2 | 3.6.5-3.el10_0.17 | RHSA-2026:71389 |
| RHEL 9.6 EUS | libsoup +1 | 2.72.0-10.el9_6.9 | RHSA-2026:68612 |
| RHEL 9.4 E4S | libsoup +1 | 2.72.0-8.el9_4.12 | RHSA-2026:69108 |
| RHEL 9.2 E4S | libsoup +1 | 2.72.0-8.el9_2.13 | RHSA-2026:69297 |
| RHEL 8.8 TUS | libsoup +1 | 2.62.3-3.el8_8.11 | RHSA-2026:69863 |
| RHEL 8.8 E4S | libsoup +1 | 2.62.3-3.el8_8.11 | RHSA-2026:69863 |
| RHEL 8.6 EUS Long Life | libsoup +1 | 2.62.3-2.el8_6.10 | RHSA-2026:70598 |
| RHEL 8.6 AUS | libsoup +1 | 2.62.3-2.el8_6.10 | RHSA-2026:70598 |
| RHEL 8.4 EUS Long Life | libsoup +1 | 2.62.3-2.el8_4.10 | RHSA-2026:70599 |
| RHEL 8.4 AUS | libsoup +1 | 2.62.3-2.el8_4.10 | RHSA-2026:70599 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | libsoup3 +2 | 3.6.5-3.el10_2.14 | ALSA-2026:68235 |
| AlmaLinux 9 | libsoup +1 | 2.72.0-16.el9_8.3 | ALSA-2026:68234 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | libsoup3 +2 | 3.6.6-1.el10_3.9 | RLSA-2026:98560 |
| Rocky Linux 9 | libsoup | 2.72.0-16.el9_8.3 | RLSA-2026:98453, RLSA-2026:68234 |
| Rocky Linux 9 | libsoup-devel | 2.72.0-17.el9_9.6 | RLSA-2026:98453 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libsoup | 3.8.1-1.1 | openSUSE-SU-2026:12365-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | libsoup +2 | 2.72.0-6.amzn2023.0.14 | ALAS2023-2026-2160 |
| Amazon Linux 2023 | libsoup3 +2 | 3.6.6-60.amzn2023 | ALAS2023-2026-2159 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | libsoup | No fix yet | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | libsoup3 +2 | 3.6.5-3.el10_2.14 | ELSA-2026-68235 |
| Oracle Linux 9 | libsoup +1 | 2.72.0-16.el9_8.3 | ELSA-2026-68234 |
Advisories 21
- RLSA-2026:98560 Important: libsoup3 security update Rocky Linux Security Advisories · Nov 13, 2026
- RLSA-2026:98453 Important: libsoup security update Rocky Linux Security Advisories · Nov 13, 2026
- WID-SEC-2026-3419 Red Hat Enterprise Linux (corosync, libevent, libsoup): Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- openSUSE-SU-2026:12365-1 libsoup-3_0-0-3.8.1-1.1 on GA media SUSE / openSUSE Security Updates · Oct 31, 2026
- ALSA-2026:68234 Moderate: libsoup security update AlmaLinux Security Advisories · Oct 29, 2026
- ALSA-2026:68235 Important: libsoup3 security update AlmaLinux Security Advisories · Oct 29, 2026
- WID-SEC-2026-2919 IBM App Connect Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 27, 2026
- RHSA-2026:68235 Red Hat Security Advisory: libsoup3 security update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RHSA-2026:71389 Red Hat Security Advisory: libsoup3 security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:70598 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:70599 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:69863 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:69297 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:69108 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:68612 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RHSA-2026:68234 Red Hat Security Advisory: libsoup security update Red Hat Security Advisories (RHSA) · Sep 24, 2026
- RLSA-2026:68234 Moderate: libsoup security update Rocky Linux Security Advisories · Sep 17, 2026
- ELSA-2026-68235 Important: libsoup3 security update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Sep 17, 2026
- ELSA-2026-68234 Moderate: libsoup security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Sep 16, 2026
- ALAS2023-2026-2159 Important: libsoup3 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 14, 2026
- ALAS2023-2026-2160 Important: libsoup security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 14, 2026
References
- RHSA-2026:68234 vendor-advisory
- RHSA-2026:68235 vendor-advisory
- RHSA-2026:68612 vendor-advisory
- RHSA-2026:69108 vendor-advisory
- RHSA-2026:69297 vendor-advisory
- RHSA-2026:69863 vendor-advisory
- RHSA-2026:70598 vendor-advisory
- RHSA-2026:70599 vendor-advisory
- RHSA-2026:71389 vendor-advisory
- RHSA-2026:98453 vendor-advisory
- RHSA-2026:98560 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-15709 vdb-entry
- RHBZ#2499922 issue-tracking
- https://gitlab.gnome.org/GNOME/libsoup/-/issues/511