Vulnerability in Mozilla Firefox

CVE-2015-2721

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.

Vulnerability class: POODLE (CVE-2014-3566)

Published · last modified .

CVSS v2 metric

CVSS v2 base score 4.3 (Medium). Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N. This CVE predates CVSS v3 and has no v3 score from NVD.

EPSS exploit prediction

EPSS: 0.033 (88.0th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 88th percentile — 88.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2015-2721: held from 0.033 to 0.033.

EPSS over last 30 days · oldest: 0.033 · newest: 0.033 · change: 0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2015-2721?
CVE-2015-2721 is a vulnerability in Mozilla Firefox, classified under Cryptographic Issues. Published 2015-07-06.
Is CVE-2015-2721 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.