CVE-2015-3278: The cipherstring parsing code in nss_compat_ossl while in multi-keyword mode does not match the expected set o

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CRITICAL 9.8REMOTEMITIGATE

CVE-2015-3278 is a critical-severity flaw (CVSS 9.8) affecting nss compat ossl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The cipherstring parsing code in nss_compat_ossl while in multi-keyword mode does not match the expected set of ciphers for a given cipher combination, which allows attackers to have unspecified impact via unknown vectors.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 26%)
CISA exploited list	No
Weakness	CWE-20
Published	2017-07-25
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: nss compat ossl project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2017-07-25 18:29 UTCPublished CVE record published
2026-06-17 00:25 UTCUpdated Record last modified

nss compat ossl project nss compat ossl MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nss-compat-ossl || rpm -q nss-compat-ossl || nss-compat-ossl --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2015-3278?

nss compat ossl: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-3278 being exploited?

CVE-2015-3278 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2015-3278 affect?

CVE-2015-3278 affects nss compat ossl. Severity is critical (CVSS 9.8). The cipherstring parsing code in nss_compat_ossl while in multi-keyword mode does not match the expected set of ciphers for a given cipher combination, which allows attackers to have unspecified impact via unknown vectors.

How urgent is CVE-2015-3278?

Priority 58/100. Critical severity; Remotely exploitable, no login, no user action

References

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