Improper Handling of Highly Compressed Data (Data Amplification) Affecting libsoup3-doc package, versions <0:3.6.6-60.amzn2023


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.59% (48th percentile)

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  • Snyk IDSNYK-AMZN2023-LIBSOUP3DOC-19821606
  • published15 Sept 2026
  • disclosed14 Jul 2026

Introduced: 14 Jul 2026

CVE-2026-15709  (opens in a new tab)
CWE-409  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 libsoup3-doc to version 0:3.6.6-60.amzn2023 or higher.
This issue was patched in ALAS2023-2026-2159.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libsoup3-doc package and not the libsoup3-doc package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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).

CVSS Base Scores

version 3.1