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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…

Medium4.3EPSS 2.8%
Published
Updated
Reserved
Assigned by
mozilla

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.

Scores

CVSS scores of CVE-2015-2721, by who scored it
Scored byCVSSScoreVector
NVDNVD · Modified2.0Medium4.3AV:N/AC:M/Au:N/C:N/I:P/A:N
EPSS (exploitation in 30 days)
2.8% · top 13% of all CVEs (6 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.3.

Weakness

Affected products

  • n/a

    • affected n/a

References (29)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .