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FreeBSD : www/varnish7 -- Denial of Service in HTTP/2 (e2d49973-785a-11f0-a1c0-0050569f0b83)

high Nessus Plugin ID 249328

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Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the e2d49973-785a-11f0-a1c0-0050569f0b83 advisory.

 Varnish Development Team reports:
 A denial of service attack can be performed on Varnish Cache servers that have the HTTP/2 protocol turned on. An attacker can create a large number of streams and immediately reset them without ever reaching the maximum number of concurrent streams allowed for the session, causing the Varnish server to consume unnecessary resources processing requests for which the response will not be delivered.
 This attack is a variant of the HTTP/2 Rapid Reset Attack, which was partially handled as VSV00013.

Tenable has extracted the preceding description block directly from the FreeBSD security advisory.

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

Solution

Update the affected packages.

See Also

https://nvd.nist.gov/vuln/detail/CVE-2025-8671

http://www.nessus.org/u?5630d0fa

Plugin Details

Severity: High

ID: 249328

File Name: freebsd_pkg_e2d49973785a11f0a1c00050569f0b83.nasl

Version: 1.1

Type: local

Published: 8/14/2025

Updated: 8/14/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

CVSS Score Source: CVE-2025-8671

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

CPE: cpe:/o:freebsd:freebsd, p-cpe:/a:freebsd:freebsd:varnish7

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 8/13/2025

Vulnerability Publication Date: 8/13/2025

Reference Information

CVE: CVE-2025-8671