CVE-2016-5396

Apache Traffic Server 6.0.0 to 6.2.0 are affected by an HPACK Bomb Attack.

Published: 2017-04-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-5396 is rated Moderate Risk (60.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.88%). EPSS rose +1.07% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-5396

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.81% 2.88% +1.07%
2 2025-03-30 1.71% 1.81% +0.09%
3 2025-03-29 — 1.71% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-5396

CVSS metrics for this CVE.

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:N/I:N/A:H 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.8 2.0 HIGH
AV:N/AC:L/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 10.0 6.9 [email protected]

Weakness enumeration for CVE-2016-5396

OS Trackers for CVE-2016-5396

vendor priority summary link
debian not yet assigned CVE-2016-5396 not yet assigned priority: Debian including 1 source packages (trafficserver), 3 status rows across 3 suites (bookworm, bullseye, sid): resolved 3. https://security-tracker.debian.org/tracker/CVE-2016-5396
ubuntu low CVE-2016-5396 low priority: Ubuntu including 1 source packages (trafficserver), 6 status rows across 6 suites (precise, trusty, upstream, xenial, yakkety, zesty): not-affected 4, DNE 1, released 1. https://ubuntu.com/security/CVE-2016-5396

Affected software / configurations for CVE-2016-5396

Vendor Product Version Raw CPE
apache traffic_server 6.0.0 cpe:2.3:a:apache:traffic_server:6.0.0:*:*:*:*:*:*:*
apache traffic_server 6.1.0 cpe:2.3:a:apache:traffic_server:6.1.0:*:*:*:*:*:*:*
apache traffic_server 6.1.1 cpe:2.3:a:apache:traffic_server:6.1.1:*:*:*:*:*:*:*
apache traffic_server 6.2.0 cpe:2.3:a:apache:traffic_server:6.2.0:*:*:*:*:*:*:*

References for CVE-2016-5396

cvelogic Threat Intelligence