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CVE-2015-2721

UnknownEPSS 3.28%

Last modified

CVE-2015-2721 is a vulnerability of currently unknown severity. 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.. EPSS estimates a 3.28% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability
3.28%

86.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
NovellSuse Linux Enterprise Software Development Kit12.0—
CanonicalUbuntu Linux12.04—
CanonicalUbuntu Linux14.04—
CanonicalUbuntu Linux14.10—
CanonicalUbuntu Linux15.04—
DebianDebian Linux7.0—
DebianDebian Linux8.0—
NovellSuse Linux Enterprise Desktop12.0—
NovellSuse Linux Enterprise Server11Sp4
NovellSuse Linux Enterprise Server12.0—
MozillaNetwork Security Services3.19—
OracleSolaris11.3—
OracleVm Server3.2—

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is 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.
How severe is CVE-2015-2721?
Severity scoring for CVE-2015-2721 is pending analysis. The EPSS model estimates a 3.28% probability of exploitation in the next 30 days.
How do I fix CVE-2015-2721?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2015-2721?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST