CVE-2017-8823

In Tor before 0.2.5.16, 0.2.6 through 0.2.8 before 0.2.8.17, 0.2.9 before 0.2.9.14, 0.3.0 before 0.3.0.13, and 0.3.1 before 0.3.1.9, there is a use-after-free in onion service v2 during intro-point expiration because the expiring list is mismanaged in certain error cases, aka TROVE-2017-013.

Published: 2017-12-03 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-8823 is rated Moderate Risk (53/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.39%). 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-2017-8823

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 2026-04-09 0.71% 0.39% -0.32%
2 2025-05-22 0.56% 0.71% +0.15%
3 2025-03-30 — 0.56% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-8823

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.0 HIGH
CVSS:3.0/AV:N/AC:H/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: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: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.
 2.2 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2017-8823

OS Trackers for CVE-2017-8823

vendor priority summary link
debian not yet assigned CVE-2017-8823 not yet assigned priority: Debian including 1 source packages (tor), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-8823
ubuntu medium CVE-2017-8823 medium priority: Ubuntu including 1 source packages (tor), 7 status rows across 7 suites (artful, bionic, cosmic, trusty, upstream, xenial, zesty): not-affected 3, released 3, ignored 1. https://ubuntu.com/security/CVE-2017-8823

Affected software / configurations for CVE-2017-8823

Vendor Product Version Raw CPE
tor_project tor < 0.2.5.16 cpe:2.3:a:tor_project:tor:*:*:*:*:*:*:*:*
tor_project tor >= 0.2.6, < 0.2.8.17 cpe:2.3:a:tor_project:tor:*:*:*:*:*:*:*:*
tor_project tor >= 0.2.9, < 0.2.9.14 cpe:2.3:a:tor_project:tor:*:*:*:*:*:*:*:*
tor_project tor >= 0.3.0, < 0.3.0.13 cpe:2.3:a:tor_project:tor:*:*:*:*:*:*:*:*
tor_project tor >= 0.3.1, < 0.3.1.9 cpe:2.3:a:tor_project:tor:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2017-8823

cvelogic Threat Intelligence