CVE-2015-6816 [Critical] | Authentication Bypass in Fedora

CVE-2015-6816 is rated High Exploit Risk (86.4/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 3.56%). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.45% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	2.11%	3.56%	+1.45%
2	2025-06-07	2.79%	2.11%	-0.68%
3	2025-03-30	—	2.79%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

2.11%

3.56%

+1.45%

2025-06-07

2.79%

2.11%

-0.68%

2025-03-30

—

2.79%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
9.8	3.0	CRITICAL	`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	5.9	[email protected]
7.5	2.0	HIGH	`AV:N/AC:L/Au:N/C:P/I:P/A:P` 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:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	10.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

9.8

3.0

CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

3.9

5.9

[email protected]

7.5

2.0

HIGH

AV:N/AC:L/Au:N/C:P/I:P/A:P 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:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

10.0

6.4

[email protected]

OS Trackers for CVE-2015-6816

vendor	priority	summary	link
`debian`	unimportant	CVE-2015-6816 unimportant priority: Debian including 2 source packages (ganglia, ganglia-web), 8 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 8.	https://security-tracker.debian.org/tracker/CVE-2015-6816
`ubuntu`	medium	CVE-2015-6816 medium priority: Ubuntu including 2 source packages (ganglia, ganglia-web), 50 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): not-affected 32, ignored 10, DNE 3, needed 3, released 2.	https://ubuntu.com/security/CVE-2015-6816

Affected software / configurations for CVE-2015-6816

Vendor	Product	Version	Raw CPE
fedoraproject	fedora	21	cpe:2.3:o:fedoraproject:fedora:21:::::::*
fedoraproject	fedora	22	cpe:2.3:o:fedoraproject:fedora:22:::::::*
fedoraproject	fedora	23	cpe:2.3:o:fedoraproject:fedora:23:::::::*
ganglia	ganglia-web	<= 3.7.0	cpe:2.3:a:ganglia:ganglia-web::::::::

References for CVE-2015-6816

URL	Tags
http://lists.fedoraproject.org/pipermail/package-announce/2015-November/170362.html	Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2015-October/169641.html	Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2015-October/169788.html	Third Party Advisory
http://www.openwall.com/lists/oss-security/2015/09/05/6	Exploit Mailing List VDB Entry
http://www.securityfocus.com/bid/92146	Third Party Advisory VDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=1260562	Exploit Issue Tracking Third Party Advisory VDB Entry
https://github.com/ganglia/ganglia-web/issues/267	Third Party Advisory
https://www.freshports.org/sysutils/ganglia-webfrontend/	Patch Third Party Advisory

URL

CVE-2015-6816

Public exploit references (Exploit-DB) for CVE-2015-6816

Exploit prediction scoring system (EPSS) score for CVE-2015-6816

Common vulnerability scoring system (CVSS) metrics for CVE-2015-6816

Weakness enumeration for CVE-2015-6816

OS Trackers for CVE-2015-6816

Affected software / configurations for CVE-2015-6816

References for CVE-2015-6816