CVE-2020-25648

Publication date 20 October 2020

Last updated 25 August 2025

Ubuntu priority

Low

Why this priority?

Cvss 3 Severity Score

7.5 · High

Score breakdown

Description

A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3. This flaw allows a remote attacker to send multiple CCS messages, causing a denial of service for servers compiled with the NSS library. The highest threat from this vulnerability is to system availability. This flaw affects NSS versions before 3.58.

Read the notes from the security team

Status

Package Ubuntu Release Status
nss 22.10 kinetic
Not affected
22.04 LTS jammy
Not affected
21.10 impish
Not affected
21.04 hirsute
Not affected
20.10 groovy Ignored end of life
20.04 LTS focal
Fixed 2:3.49.1-1ubuntu1.7
18.04 LTS bionic
Fixed 2:3.35-2ubuntu2.14
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected

Notes

leosilva

From SUSE and Rhel: This issue affects servers which are compiled against the NSS library. Other consumers of NSS like firefox etc are not affected by this flaw.

eslerm

CCS handling introduced after 3.28.4 with revision c3eba3a9483abede4c35fa92b5c950a35cd9b639 and others

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
nss

Severity score breakdown

Parameter Value
Base score 7.5 · High
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

Other references