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Fencer Intel
medium 5.3

CVE-2018-9251 json

The xz_decomp function in xzlib.c in libxml2 2.9.8, if --with-lzma is used, allows remote attackers to cause a denial of service (infinite…

published 2018-04-04 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-20845

cvss
5.3
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.4%
EPSS 2.4% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known

Summary

The xz_decomp function in xzlib.c in libxml2 2.9.8, if --with-lzma is used, allows remote attackers to cause a denial of service (infinite loop) via a crafted XML file that triggers LZMA_MEMLIMIT_ERROR, as demonstrated by xmllint, a different vulnerability than CVE-2015-8035.

Patch / fix

  • libxml2 RHEL 8 2.9.7-7.el8
  • python3-libxml2 RHEL 8 2.9.7-7.el8

red hat advisories RHSA-2020:1827

  • libxml2 SLE Module for Basesystem 15 2.9.7-3.3.1
  • python-libxml2-python SLE Module for Basesystem 15 2.9.7-3.3.1
  • libxml2 SLES for SAP 12 SP3, SLES 12 SP3, SLED 12 SP3 +1 more 2.9.4-46.15.1
  • python-libxml2 SLES for SAP 12 SP3, SLES 12 SP3, SLED 12 SP3 2.9.4-46.15.1

suse advisories SUSE-SU-2018:3080-1SUSE-SU-2018:3081-1

  • libxml2 openSUSE Tumbleweed 2.9.12-1.2

opensuse advisories openSUSE-SU-2024:11016-1

  • libxml2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +17 more 2.9.8-r1

alpine advisories ALPINE-CVE-2018-9251

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libxml2 Arch Linux 2.9.8-5
  • lib32-libxml2 Arch Linux 2.9.8-4

arch linux advisories AVG-672AVG-673

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-9251 updated cvss 3.5

libxml2: infinite loop in xz_decomp function in xzlib.c

  • Red Hat Enterprise Linux AppStream (v. 8) libxml2-devel 2.9.7-7.el8, libxml2-debuginfo 2.9.7-7.el8, libxml2-debugsource 2.9.7-7.el8, python3-libxml2-debuginfo 2.9.7-7.el8 Red Hat Enterprise Linux BaseOS (v. 8) libxml2 2.9.7-7.el8, python3-libxml2 2.9.7-7.el8
    fixed: vendor fix RHSA-2020:1827
  • Red Hat Enterprise Linux 5 libxml2 Red Hat Enterprise Linux 6 libxml2, libxml2-python Red Hat Enterprise Linux 7 libxml2, libxml2-python Red Hat JBoss Core Services libxml2 Red Hat JBoss Web Server 3 libxml2
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.36% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • bugzilla.gnome.org https://bugzilla.gnome.org/show_bug.cgi?id=794914 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 5.3 CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
NVD 2.0 2.6 AV:N/AC:H/Au:N/C:N/I:N/A:P

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.