CVE-2015-2156 [High] | Input Validation Bypass in Netty

CVE-2015-2156 is rated Moderate Risk (64.2/100): CVSS High severity, with high exploitation likelihood (EPSS 5.43%, 92th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +2.16% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	3.27%	5.43%	+2.16%
2	2026-01-26	0.92%	3.27%	+2.35%
3	2025-10-13	—	0.92%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

3.27%

5.43%

+2.16%

2026-01-26

0.92%

3.27%

+2.35%

2025-10-13

—

0.92%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.0	HIGH	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:N) Service keeps running; no real outage angle.	3.9	3.6	[email protected]
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:P/I:N/A:N` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:M) Exploitation needs some favorable conditions, but not exceptional ones. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:N) No availability impact.	8.6	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

7.5

3.0

HIGH

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N): No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:N): Data isn’t meaningfully altered or forged.
Availability (A:N): Service keeps running; no real outage angle.

3.9

3.6

[email protected]

4.3

2.0

MEDIUM

AV:N/AC:M/Au:N/C:P/I:N/A:N Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:M): Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:N): No availability impact.

8.6

2.9

[email protected]

OS Trackers for CVE-2015-2156

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2015-2156 not yet assigned priority: Debian including 1 source packages (netty), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2015-2156
`redhat`	low	—	https://access.redhat.com/security/cve/CVE-2015-2156
`ubuntu`	medium	CVE-2015-2156 medium priority: Ubuntu including 3 source packages (netty, netty-3.9, netty3.1), 75 status rows across 25 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, precise, questing, trusty, upstream, vivid, wily, xenial, yakkety, zesty): DNE 38, not-affected 19, ignored 13, needed 2, released 2, needs-triage 1.	https://ubuntu.com/security/CVE-2015-2156

Affected software / configurations for CVE-2015-2156

Vendor	Product	Version	Raw CPE
netty	netty	<= 3.9.7	cpe:2.3:a:netty:netty::::::::
netty	netty	3.10.0	cpe:2.3:a:netty:netty:3.10.0:::::::*
netty	netty	3.10.1	cpe:2.3:a:netty:netty:3.10.1:::::::*
netty	netty	3.10.2	cpe:2.3:a:netty:netty:3.10.2:::::::*
netty	netty	4.0.0	cpe:2.3:a:netty:netty:4.0.0:::::::*
netty	netty	4.0.1	cpe:2.3:a:netty:netty:4.0.1:::::::*
netty	netty	4.0.2	cpe:2.3:a:netty:netty:4.0.2:::::::*
netty	netty	4.0.3	cpe:2.3:a:netty:netty:4.0.3:::::::*
netty	netty	4.0.4	cpe:2.3:a:netty:netty:4.0.4:::::::*
netty	netty	4.0.5	cpe:2.3:a:netty:netty:4.0.5:::::::*
netty	netty	4.0.6	cpe:2.3:a:netty:netty:4.0.6:::::::*
netty	netty	4.0.7	cpe:2.3:a:netty:netty:4.0.7:::::::*
netty	netty	4.0.8	cpe:2.3:a:netty:netty:4.0.8:::::::*
netty	netty	4.0.9	cpe:2.3:a:netty:netty:4.0.9:::::::*
netty	netty	4.0.10	cpe:2.3:a:netty:netty:4.0.10:::::::*
netty	netty	4.0.11	cpe:2.3:a:netty:netty:4.0.11:::::::*
netty	netty	4.0.12	cpe:2.3:a:netty:netty:4.0.12:::::::*
netty	netty	4.0.13	cpe:2.3:a:netty:netty:4.0.13:::::::*
netty	netty	4.0.14	cpe:2.3:a:netty:netty:4.0.14:::::::*
netty	netty	4.0.15	cpe:2.3:a:netty:netty:4.0.15:::::::*
netty	netty	4.0.16	cpe:2.3:a:netty:netty:4.0.16:::::::*
netty	netty	4.0.17	cpe:2.3:a:netty:netty:4.0.17:::::::*
netty	netty	4.0.18	cpe:2.3:a:netty:netty:4.0.18:::::::*
netty	netty	4.0.19	cpe:2.3:a:netty:netty:4.0.19:::::::*
netty	netty	4.0.20	cpe:2.3:a:netty:netty:4.0.20:::::::*
netty	netty	4.0.21	cpe:2.3:a:netty:netty:4.0.21:::::::*
netty	netty	4.0.22	cpe:2.3:a:netty:netty:4.0.22:::::::*
netty	netty	4.0.23	cpe:2.3:a:netty:netty:4.0.23:::::::*
netty	netty	4.0.24	cpe:2.3:a:netty:netty:4.0.24:::::::*
netty	netty	4.0.25	cpe:2.3:a:netty:netty:4.0.25:::::::*
netty	netty	4.0.26	cpe:2.3:a:netty:netty:4.0.26:::::::*
netty	netty	4.0.27	cpe:2.3:a:netty:netty:4.0.27:::::::*
netty	netty	4.1.0	cpe:2.3:a:netty:netty:4.1.0:beta1::::::
netty	netty	4.1.0	cpe:2.3:a:netty:netty:4.1.0:beta2::::::
netty	netty	4.1.0	cpe:2.3:a:netty:netty:4.1.0:beta3::::::
netty	netty	4.1.0	cpe:2.3:a:netty:netty:4.1.0:beta4::::::
lightbend	play_framework	2.0	cpe:2.3:a:lightbend:play_framework:2.0:rc3::::::
lightbend	play_framework	2.0	cpe:2.3:a:lightbend:play_framework:2.0:rc4::::::
lightbend	play_framework	2.0	cpe:2.3:a:lightbend:play_framework:2.0:rc5::::::
lightbend	play_framework	2.0.2	cpe:2.3:a:lightbend:play_framework:2.0.2:::::::*
lightbend	play_framework	2.0.2	cpe:2.3:a:lightbend:play_framework:2.0.2:rc1::::::
lightbend	play_framework	2.0.2	cpe:2.3:a:lightbend:play_framework:2.0.2:rc2::::::
lightbend	play_framework	2.0.3	cpe:2.3:a:lightbend:play_framework:2.0.3:::::::*
lightbend	play_framework	2.0.3	cpe:2.3:a:lightbend:play_framework:2.0.3:rc1::::::
lightbend	play_framework	2.0.3	cpe:2.3:a:lightbend:play_framework:2.0.3:rc2::::::
lightbend	play_framework	2.0.4	cpe:2.3:a:lightbend:play_framework:2.0.4:::::::*
lightbend	play_framework	2.0.4	cpe:2.3:a:lightbend:play_framework:2.0.4:rc1::::::
lightbend	play_framework	2.0.4	cpe:2.3:a:lightbend:play_framework:2.0.4:rc2::::::
lightbend	play_framework	2.0.5	cpe:2.3:a:lightbend:play_framework:2.0.5:::::::*
lightbend	play_framework	2.0.5	cpe:2.3:a:lightbend:play_framework:2.0.5:rc1::::::
lightbend	play_framework	2.0.5	cpe:2.3:a:lightbend:play_framework:2.0.5:rc2::::::
lightbend	play_framework	2.0.6	cpe:2.3:a:lightbend:play_framework:2.0.6:::::::*
lightbend	play_framework	2.0.7	cpe:2.3:a:lightbend:play_framework:2.0.7:::::::*
lightbend	play_framework	2.0.8	cpe:2.3:a:lightbend:play_framework:2.0.8:::::::*
lightbend	play_framework	2.1.0	cpe:2.3:a:lightbend:play_framework:2.1.0:::::::*
lightbend	play_framework	2.1.1	cpe:2.3:a:lightbend:play_framework:2.1.1:::::::*
lightbend	play_framework	2.1.1	cpe:2.3:a:lightbend:play_framework:2.1.1:rc1::::::
lightbend	play_framework	2.2.0	cpe:2.3:a:lightbend:play_framework:2.2.0:::::::*
lightbend	play_framework	2.2.1	cpe:2.3:a:lightbend:play_framework:2.2.1:::::::*
lightbend	play_framework	2.2.2	cpe:2.3:a:lightbend:play_framework:2.2.2:::::::*
lightbend	play_framework	2.2.6	cpe:2.3:a:lightbend:play_framework:2.2.6:::::::*
lightbend	play_framework	2.3.0	cpe:2.3:a:lightbend:play_framework:2.3.0:::::::*
lightbend	play_framework	2.3.0	cpe:2.3:a:lightbend:play_framework:2.3.0:rc1::::::
lightbend	play_framework	2.3.0	cpe:2.3:a:lightbend:play_framework:2.3.0:rc2::::::
lightbend	play_framework	2.3.1	cpe:2.3:a:lightbend:play_framework:2.3.1:::::::*
lightbend	play_framework	2.3.2	cpe:2.3:a:lightbend:play_framework:2.3.2:::::::*
lightbend	play_framework	2.3.2	cpe:2.3:a:lightbend:play_framework:2.3.2:rc1::::::
lightbend	play_framework	2.3.2	cpe:2.3:a:lightbend:play_framework:2.3.2:rc2::::::
lightbend	play_framework	2.3.3	cpe:2.3:a:lightbend:play_framework:2.3.3:::::::*
lightbend	play_framework	2.3.4	cpe:2.3:a:lightbend:play_framework:2.3.4:::::::*
lightbend	play_framework	2.3.5	cpe:2.3:a:lightbend:play_framework:2.3.5:::::::*
lightbend	play_framework	2.3.6	cpe:2.3:a:lightbend:play_framework:2.3.6:::::::*
lightbend	play_framework	2.3.7	cpe:2.3:a:lightbend:play_framework:2.3.7:::::::*
lightbend	play_framework	2.3.8	cpe:2.3:a:lightbend:play_framework:2.3.8:::::::*
playframework	play_framework	2.0	cpe:2.3:a:playframework:play_framework:2.0:::::::*
playframework	play_framework	2.0	cpe:2.3:a:playframework:play_framework:2.0:beta::::::
playframework	play_framework	2.0	cpe:2.3:a:playframework:play_framework:2.0:rc1::::::
playframework	play_framework	2.0	cpe:2.3:a:playframework:play_framework:2.0:rc2::::::
playframework	play_framework	2.0.1	cpe:2.3:a:playframework:play_framework:2.0.1:::::::*
playframework	play_framework	2.1.1	cpe:2.3:a:playframework:play_framework:2.1.1:2.9.x-backport::::::

References for CVE-2015-2156

URL	Tags
http://lists.fedoraproject.org/pipermail/package-announce/2015-June/159379.html	Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2015-May/159166.html	Third Party Advisory
http://netty.io/news/2015/05/08/3-9-8-Final-and-3.html	Vendor Advisory
http://www.openwall.com/lists/oss-security/2015/05/17/1	Mailing List Third Party Advisory
http://www.securityfocus.com/bid/74704	Third Party Advisory VDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=1222923	Issue Tracking Third Party Advisory
https://github.com/netty/netty/pull/3754	Third Party Advisory
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	Third Party Advisory

URL

CVE-2015-2156

Exploit prediction scoring system (EPSS) score for CVE-2015-2156

Common vulnerability scoring system (CVSS) metrics for CVE-2015-2156

Weakness enumeration for CVE-2015-2156

GitHub Security Advisory for CVE-2015-2156

OS Trackers for CVE-2015-2156

Affected software / configurations for CVE-2015-2156

References for CVE-2015-2156