CVE-2017-8921

In FlightGear before 2017.2.1, the FGCommand interface allows overwriting any file the user has write access to, but not with arbitrary data: only with the contents of a FlightGear flightplan (XML). A resource such as a malicious third-party aircraft could exploit this to damage files belonging to the user. Both this issue and CVE-2016-9956 are directory traversal vulnerabilities in Autopilot/route_mgr.cxx - this one exists because of an incomplete fix for CVE-2016-9956.

Published: 2017-05-12 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-8921 is rated Moderate Risk (48/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.29%). 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-2017-8921

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 2026-05-16 0.59% 0.29% -0.30%
2 2025-03-30 0.70% 0.59% -0.11%
3 2025-03-29 — 0.70% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-8921

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:H/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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N 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:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2017-8921

OS Trackers for CVE-2017-8921

vendor priority summary link
debian not yet assigned CVE-2017-8921 not yet assigned priority: Debian including 1 source packages (flightgear), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-8921
ubuntu medium CVE-2017-8921 medium priority: Ubuntu including 1 source packages (flightgear), 22 status rows across 22 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial, yakkety, zesty): not-affected 17, ignored 2, DNE 1, needed 1, released 1. https://ubuntu.com/security/CVE-2017-8921

Affected software / configurations for CVE-2017-8921

Vendor Product Version Raw CPE
flightgear flightgear <= 2017.2 cpe:2.3:a:flightgear:flightgear:*:*:*:*:*:*:*:*

References for CVE-2017-8921

cvelogic Threat Intelligence