CVE-2015-2721
nss - security update
EPSS 0.51%
Description
Mozilla Network Security Services (NSS) before 3.19, as used in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, Thunderbird before 38.1, and other products, does not properly determine state transitions for the TLS state machine, which allows man-in-the-middle attackers to defeat cryptographic protection mechanisms by blocking messages, as demonstrated by removing a forward-secrecy property by blocking a ServerKeyExchange message, aka a "SMACK SKIP-TLS" issue.
How to fix CVE-2015-2721
To remediate CVE-2015-2721, upgrade the affected package to a fixed version below.
- —upgrade to 31.8.0-1~deb7u1 or later
- —upgrade to 31.8.0esr-1~deb7u1 or later
- —upgrade to 2:3.19.1-1 or later
- —upgrade to 3.12.8-1+squeeze12 or later
- —upgrade to 2:3.14.5-1+deb7u5 or later
Is CVE-2015-2721 being exploited?
Low — EPSS is 0.5%, meaning exploitation activity has not been observed at scale.
Affected packages (5)
- from 0, < 31.8.0-1~deb7u1
- from 0, < 31.8.0esr-1~deb7u1
- from 0, < 2:3.19.1-1
- from 0, < 3.12.8-1+squeeze12
- from 0, < 2:3.14.5-1+deb7u5