CVE-2015-2156

CVE-2015-2156 is a high-severity vulnerability in Netty with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

• Severity: High (CVSS 3.x base score 7.5)
• CVSS v2: 4.3
• EPSS exploit prediction: 5% (92nd percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-20
• Affected product: Netty
• Published: 2017-10-18
• Last modified: 2026-06-17

Description

Netty before 3.9.8.Final, 3.10.x before 3.10.3.Final, 4.0.x before 4.0.28.Final, and 4.1.x before 4.1.0.Beta5 and Play Framework 2.x before 2.3.9 might allow remote attackers to bypass the httpOnly flag on cookies and obtain sensitive information by leveraging improper validation of cookie name and value characters.

Frequently asked questions

What is CVE-2015-2156?

Netty before 3.9.8.Final, 3.10.x before 3.10.3.Final, 4.0.x before 4.0.28.Final, and 4.1.x before 4.1.0.Beta5 and Play Framework 2.x before 2.3.9 might allow remote attackers to bypass the httpOnly flag on cookies and obtain sensitive information by leveraging improper validation of cookie name and value characters.

How severe is CVE-2015-2156?

CVE-2015-2156 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2015-2156 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-2156?

CVE-2015-2156 primarily affects Netty. In total, 110 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-2156?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2015-2156 published?

CVE-2015-2156 was published on 2017-10-18 and last updated on 2026-06-17.

References

• http://lists.fedoraproject.org/pipermail/package-announce/2015-June/159379.html
• http://lists.fedoraproject.org/pipermail/package-announce/2015-May/159166.html
• http://netty.io/news/2015/05/08/3-9-8-Final-and-3.html
• http://www.openwall.com/lists/oss-security/2015/05/17/1
• http://www.securityfocus.com/bid/74704
• https://bugzilla.redhat.com/show_bug.cgi?id=1222923
• https://github.com/netty/netty/pull/3754
• https://lists.apache.org/thread.html/9317fd092b257a0815434b116a8af8daea6e920b6673f4fd5583d5fe%40%3Ccommits.druid.apache.org%3E
• https://lists.apache.org/thread.html/a19bb1003b0d6cd22475ba83c019b4fc7facfef2a9e13f71132529d3%40%3Ccommits.cassandra.apache.org%3E
• https://lists.apache.org/thread.html/dc1275aef115bda172851a231c76c0932d973f9ffd8bc375c4aba769%40%3Ccommits.cassandra.apache.org%3E
• https://lists.apache.org/thread.html/ff8dcfe29377088ab655fda9d585dccd5b1f07fabd94ae84fd60a7f8%40%3Ccommits.pulsar.apache.org%3E
• https://www.playframework.com/security/vulnerability/CVE-2015-2156-HttpOnlyBypass

Affected products (110)

• cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:3.10.0:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:3.10.1:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:3.10.2:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.0:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.1:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.2:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.3:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.4:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.5:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.6:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.7:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.8:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.9:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.10:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.11:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.12:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.13:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.14:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.15:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.16:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.17:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.18:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.19:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.20:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.21:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.22:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.23:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.24:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.25:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.26:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.0.27:*:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.1.0:beta1:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.1.0:beta2:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.1.0:beta3:*:*:*:*:*:*
• cpe:2.3:a:netty:netty:4.1.0:beta4:*:*:*:*:*:*
• cpe:2.3:a:lightbend:play_framework:2.0:rc3:*:*:*:*:*:*
• cpe:2.3:a:lightbend:play_framework:2.0:rc4:*:*:*:*:*:*
• cpe:2.3:a:lightbend:play_framework:2.0:rc5:*:*:*:*:*:*
• cpe:2.3:a:lightbend:play_framework:2.0.2:*:*:*:*:*:*:*

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