CVE-2017-18258

The xz_head function in xzlib.c in libxml2 before 2.9.6 allows remote attackers to cause a denial of service (memory consumption) via a crafted LZMA file, because the decoder functionality does not restrict memory usage to what is required for a legitimate file.

Published: 2018-04-08 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-18258 is rated Moderate Risk (57.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.71%). EPSS rose +1.81% over the last day, indicating growing attacker interest. 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-2017-18258

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 0.90% 2.71% +1.81%
2 2026-05-12 0.61% 0.90% +0.29%
3 2026-05-11 — 0.61% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-18258

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/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: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.
 2.8 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]

Weakness enumeration for CVE-2017-18258

GitHub Security Advisory for CVE-2017-18258

GHSA-882p-jqgm-f45g · Severity: medium · Ecosystem: rubygems — Uncontrolled resource consumption in nokogiri

OS Trackers for CVE-2017-18258

vendor priority summary link
debian low CVE-2017-18258 low priority: Debian including 1 source packages (libxml2), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-18258
redhat low — https://access.redhat.com/security/cve/CVE-2017-18258
suse low CVE-2017-18258 severity low: SUSE including 58 source package names (0.9.1:libxml2-2-2.9.4-46.15.1, 1.0.0:libxml2-2-2.9.4-46.15.1, …), 138 product×package rows across 66 product lines (Container caasp/v4/default-http-backend, Container caasp/v4/dnsmasq-nanny, … (66 product lines)): Fixed 123, Known Not Affected 15. https://www.suse.com/security/cve/CVE-2017-18258/
ubuntu low CVE-2017-18258 low priority: Ubuntu including 1 source packages (libxml2), 5 status rows across 5 suites (artful, bionic, trusty, upstream, xenial): released 4, ignored 1. https://ubuntu.com/security/CVE-2017-18258

Affected software / configurations for CVE-2017-18258

Vendor Product Version Raw CPE
xmlsoft libxml2 < 2.9.6 cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

References for CVE-2017-18258

cvelogic Threat Intelligence