Vulnerability in Red Hat Enterprise Linux 10
CVE-2026-15709
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).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.009 (58.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 58.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.009 · change: +0.003
Affected products
Weakness classification (CWE)
References
- access.redhat.com/security/cve/CVE-2026-15709 (vdb-entry)
- bugzilla.redhat.com/show_bug.cgi (issue-tracking)
- gitlab.gnome.org/GNOME/libsoup/-/issues/511
- access.redhat.com/errata/RHSA-2026:68234 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:68235 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:68612 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:69108 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:69297 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:69863 (vendor-advisory)
- access.redhat.com/errata/RHSA-2026:70599 (vendor-advisory)
Frequently asked questions
- What is CVE-2026-15709?
- CVE-2026-15709 is a high-severity vulnerability in Red Hat Enterprise Linux 10, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-07-14.
- How severe is CVE-2026-15709?
- High severity. CVSS v3 base score is 7.5 out of 10.