CVE-2015-4170

Race condition in the ldsem_cmpxchg function in drivers/tty/tty_ldsem.c in the Linux kernel before 3.13-rc4-next-20131218 allows local users to cause a denial of service (ldsem_down_read and ldsem_down_write deadlock) by establishing a new tty thread during shutdown of a previous tty thread.

Published: 2016-05-02 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-4170 is rated Low Risk (27.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.33%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2015-4170

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 0.06% 0.33% +0.27%
2 2025-05-10 0.04% 0.06% +0.02%
3 2025-03-30 — 0.04% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-4170

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.7 3.0 MEDIUM
CVSS:3.0/AV:L/AC:H/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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.
 1.0 3.6 [email protected]
4.7 2.0 MEDIUM
AV:L/AC:M/Au:N/C:N/I:N/A:C Click to expand
Access vector (AV:L)
Requires local access to the target system.
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:C)
Complete availability impact.
 3.4 6.9 [email protected]

Weakness enumeration for CVE-2015-4170

OS Trackers for CVE-2015-4170

vendor priority summary link
debian not yet assigned CVE-2015-4170 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-4170
redhat medium — https://access.redhat.com/security/cve/CVE-2015-4170
ubuntu medium CVE-2015-4170 medium priority: Ubuntu including 31 source packages (linux, linux-2.6, …), 231 status rows across 8 suites (precise, trusty, upstream, utopic, vivid, wily, xenial, yakkety): DNE 156, not-affected 37, released 31, ignored 7. https://ubuntu.com/security/CVE-2015-4170

Affected software / configurations for CVE-2015-4170

Vendor Product Version Raw CPE
linux linux_kernel <= 3.13.3 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
redhat enterprise_linux_compute_node_eus 7.1 cpe:2.3:o:redhat:enterprise_linux_compute_node_eus:7.1:*:*:*:*:*:*:*
redhat enterprise_linux_for_ibm_z_systems_eus 7.1_s390x cpe:2.3:o:redhat:enterprise_linux_for_ibm_z_systems_eus:7.1_s390x:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_big_endian_eus 7.1_ppc64 cpe:2.3:o:redhat:enterprise_linux_for_power_big_endian_eus:7.1_ppc64:*:*:*:*:*:*:*
redhat enterprise_linux_for_power_little_endian_eus 7.1_ppc64le cpe:2.3:o:redhat:enterprise_linux_for_power_little_endian_eus:7.1_ppc64le:*:*:*:*:*:*:*
redhat enterprise_linux_server_eus 7.1 cpe:2.3:o:redhat:enterprise_linux_server_eus:7.1:*:*:*:*:*:*:*

References for CVE-2015-4170

cvelogic Threat Intelligence