AlmaLinux 9.2 [TuxCare] Security Update: libsoup / libsoup-devel / libsoup-doc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1790076145)

high Nessus Plugin ID 360054

Synopsis

The AlmaLinux host is missing one or more security updates.

Description

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1790076145 advisory.

- 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).
(CVE-2026-15709)

- A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or less. A remote, unauthenticated attacker can exploit this by sending a non-compliant, oversized control frame. Because the parser handles this protocol violation improperly instead of throwing an immediate connection termination error, it triggers a internal processing crash, resulting in a remote denial of service (DoS) for applications utilizing libsoup WebSockets. (CVE-2026-15711)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages based on the guidance in TuxCare advisory ALMALINUX9.2:CLSA-2026:1790076145.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1790076145

http://www.nessus.org/u?62b5c604

Plugin Details

Severity: High

ID: 360054

File Name: tuxcare_alma_linux_9.2_CLSA-2026-1790076145.nasl

Version: 1.1

Type: Local

Published: 10/1/2026

Updated: 10/1/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.61

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-15711

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/AlmaLinux/release, Host/AlmaLinux/rpm-list, Host/OS/extended-third-party

Exploit Ease: No known exploits are available

Patch Publication Date: 9/22/2026

Vulnerability Publication Date: 7/14/2026

Reference Information

CVE: CVE-2026-15709, CVE-2026-15711

CLSA: 2026:1790076145