CVE-2015-4645 [Medium] | Integer Overflow in Squashfs

CVE-2015-4645 is rated Moderate Risk (55.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.16%). EPSS rose +3.00% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.16%	3.16%	+3.00%
2	2025-03-30	0.31%	0.16%	-0.15%
3	2025-03-29	—	0.31%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.16%

3.16%

+3.00%

2025-03-30

0.31%

0.16%

-0.15%

2025-03-29

—

0.31%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.5	3.1	MEDIUM	`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. 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:R) A real person has to do something—click, install, enable—otherwise it doesn’t land. 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.	1.8	3.6	[email protected]
4.3	2.0	MEDIUM	`AV:N/AC:M/Au:N/C:N/I:N/A:P` 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:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	8.6	2.9	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.5

3.1

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R): A real person has to do something—click, install, enable—otherwise it doesn’t land.
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.

1.8

3.6

[email protected]

4.3

2.0

MEDIUM

AV:N/AC:M/Au:N/C:N/I:N/A:P 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:N): No confidentiality impact.
Integrity impact (I:N): No integrity impact.
Availability impact (A:P): Partial availability impact.

8.6

2.9

[email protected]

OS Trackers for CVE-2015-4645

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2015-4645 not yet assigned priority: Debian including 1 source packages (squashfs-tools), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2015-4645
`gentoo`	normal	CVE-2015-4645: 1 GLSA(s) (201701-73), 1 atom(s) (sys-fs/squashfs-tools); latest impact normal.	https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2015-4645
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2015-4645
`suse`	medium	CVE-2015-4645 severity moderate: SUSE including 11 source package names (2.0.4-5.8.118:squashfs-4.6.1-150300.3.3.1, 9.24.43-10.1:squashfs-4.6.1-150300.3.3.1, …), 41 product×package rows across 40 product lines (Container bci/kiwi, Container suse/sle-micro-rancher/5.2, … (40 product lines)): Fixed 38, Known Not Affected 3.	https://www.suse.com/security/cve/CVE-2015-4645/
`ubuntu`	low	CVE-2015-4645 low priority: Ubuntu including 1 source packages (squashfs-tools), 13 status rows across 13 suites (artful, bionic, cosmic, disco, precise, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): ignored 7, not-affected 4, DNE 1, released 1.	https://ubuntu.com/security/CVE-2015-4645

Affected software / configurations for CVE-2015-4645

Vendor	Product	Version	Raw CPE
squashfs_project	squashfs	<= 4.3	cpe:2.3:a:squashfs_project:squashfs::::::::
fedoraproject	fedora	21	cpe:2.3:o:fedoraproject:fedora:21:::::::*
fedoraproject	fedora	22	cpe:2.3:o:fedoraproject:fedora:22:::::::*

References for CVE-2015-4645

URL	Tags
http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162171.html	Third Party Advisory
http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162226.html	Third Party Advisory
http://www.securityfocus.com/bid/75272	Third Party Advisory VDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=1234886	Issue Tracking Third Party Advisory VDB Entry
https://github.com/devttys0/sasquatch/pull/5	Third Party Advisory
https://github.com/plougher/squashfs-tools/commit/f95864afe8833fe3ad782d714b41378e860977b1	Third Party Advisory
https://security.gentoo.org/glsa/201701-73	Third Party Advisory VDB Entry

URL

CVE-2015-4645

Exploit prediction scoring system (EPSS) score for CVE-2015-4645

Common vulnerability scoring system (CVSS) metrics for CVE-2015-4645

Weakness enumeration for CVE-2015-4645

OS Trackers for CVE-2015-4645

Affected software / configurations for CVE-2015-4645

References for CVE-2015-4645