A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval() function of libxml2 through 2.9.8 when parsing an invali
A NULL pointer dereference vulnerability exists in the xpath.c:xmlXPathCompOpEval() function of libxml2 through 2.9.8 when parsing an invalid XPath expression in the XPATH_OP_AND or XPATH_OP_OR case. Applications processing untrusted XSL format inputs with the use of the libxml2 library may be vulnerable to a denial of service attack due to a crash of the application.
- Published
- Jul 19, 2018
- Updated
- Jun 16, 2026
- EPSS
- 3.7% · 89th percentile
- CWE
- CWE-476
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Report tools
Action score
27
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.7%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| xmlsoft | libxml2 | cpe:2.3:a:xmlsoft:libxml2 |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux18.04
- debian debian linuxall versions
- xmlsoft libxml2up to 2.9.8 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | libxml2 | before 2.9.8-r1 | 2.9.8-r1 |
| Debian:12 | libxml2 | before 2.9.10+dfsg-2 | 2.9.10+dfsg-2 |
| Debian:8 | libxml2 | before 2.9.1+dfsg1-5+deb8u7 | 2.9.1+dfsg1-5+deb8u7 |
| Debian:9 | libxml2 | before 2.9.4+dfsg1-2.2+deb9u3 | 2.9.4+dfsg1-2.2+deb9u3 |
| openSUSE:Tumbleweed | libxml2 | before 2.9.12-1.2 | 2.9.12-1.2 |
| openSUSE:Tumbleweed | rmt-server | before 2.6.13-1.1 | 2.6.13-1.1 |
| Red Hat:enterprise_linux:7::client | libxml2 | before 0:2.9.1-6.el7.4 | 0:2.9.1-6.el7.4 |
| Red Hat:enterprise_linux:7::client | libxml2-debuginfo | before 0:2.9.1-6.el7.4 | 0:2.9.1-6.el7.4 |
| Red Hat:enterprise_linux:7::client | libxml2-devel | before 0:2.9.1-6.el7.4 | 0:2.9.1-6.el7.4 |
| Red Hat:enterprise_linux:7::client | libxml2-python | before 0:2.9.1-6.el7.4 | 0:2.9.1-6.el7.4 |
| Red Hat:enterprise_linux:7::client | libxml2-static | before 0:2.9.1-6.el7.4 | 0:2.9.1-6.el7.4 |
| Red Hat:enterprise_linux:7::hypervisor | cockpit-ovirt | before 0:0.13.10-1.el7ev | 0:0.13.10-1.el7ev |
| Red Hat:enterprise_linux:7::hypervisor | cockpit-ovirt-dashboard | before 0:0.13.10-1.el7ev | 0:0.13.10-1.el7ev |
| Red Hat:enterprise_linux:7::hypervisor | redhat-release-virtualization-host | before 0:4.3.9-2.el7ev | 0:4.3.9-2.el7ev |
| Red Hat:enterprise_linux:7::hypervisor | redhat-virtualization-host | before 0:4.3.9-20200324.0.el7_8 | 0:4.3.9-20200324.0.el7_8 |
| Red Hat:enterprise_linux:7::hypervisor | redhat-virtualization-host-image-update | before 0:4.3.9-20200324.0.el7_8 | 0:4.3.9-20200324.0.el7_8 |
| Red Hat:enterprise_linux:7::hypervisor | redhat-virtualization-host-image-update-placeholder | before 0:4.3.9-2.el7ev | 0:4.3.9-2.el7ev |
| Red Hat:enterprise_linux:8::appstream | libxml2-debuginfo | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| Red Hat:enterprise_linux:8::appstream | libxml2-debugsource | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| Red Hat:enterprise_linux:8::appstream | libxml2-devel | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| Red Hat:enterprise_linux:8::appstream | python3-libxml2-debuginfo | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| Red Hat:enterprise_linux:8::baseos | libxml2 | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| Red Hat:enterprise_linux:8::baseos | python3-libxml2 | before 0:2.9.7-7.el8 | 0:2.9.7-7.el8 |
| RubyGems | nokogiri | before 1.8.5 | 1.8.5 |
+7
Same product
canonical: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-3493The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities KEV76This week
- CVE-2017-14492Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via67This week
- CVE-2017-14493Stack-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code vi64This week
- CVE-2016-4553client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which al58Plan
- CVE-2017-14495Memory leak in dnsmasq before 2.78, when the --add-mac, --add-cpe-id or --add-subnet option is specified, allows remote attackers to cause a55Plan
- CVE-2016-4054Buffer overflow in Squid 3.x before 3.5.17 and 4.x before 4.0.9 allows remote attackers to execute arbitrary code via crafted Edge Side Incl55Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:libxml2 | 2.9.8-r1 · Alpine:v3.10 | Package registry (OSV) |
| debian:libxml2 | 2.9.10+dfsg-2 · Debian:12 | Package registry (OSV) |
| opensuse:libxml2 | 2.9.12-1.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| opensuse:rmt-server | 2.6.13-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:cockpit-ovirt | 0:0.13.10-1.el7ev · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:cockpit-ovirt-dashboard | 0:0.13.10-1.el7ev · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:libxml2 | 0:2.9.1-6.el7.4 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxml2-debuginfo | 0:2.9.1-6.el7.4 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxml2-debugsource | 0:2.9.7-7.el8 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:libxml2-devel | 0:2.9.1-6.el7.4 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxml2-python | 0:2.9.1-6.el7.4 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:libxml2-static | 0:2.9.1-6.el7.4 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:redhat-release-virtualization-host | 0:4.3.9-2.el7ev · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:redhat-virtualization-host | 0:4.3.9-20200324.0.el7_8 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:redhat-virtualization-host-image-update | 0:4.3.9-20200324.0.el7_8 · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| red hat:redhat-virtualization-host-image-update-placeholder | 0:4.3.9-2.el7ev · Red Hat:enterprise_linux:7::hypervisor | Package registry (OSV) |
| RubyGems:nokogiri | 1.8.5 | Package registry (OSV) |
| suse:libxml2 | 2.9.7-3.3.1 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
| suse:libxml2-python | 2.7.6-0.77.15.1 · SUSE:Linux Enterprise Point of Sale 11 SP3 | Package registry (OSV) |
| suse:python-libxml2 | 2.9.4-46.15.1 · SUSE:Linux Enterprise Desktop 12 SP3 | Package registry (OSV) |
| suse:python-libxml2-python | 2.9.7-3.3.1 · SUSE:Linux Enterprise Module for Basesystem 15 | Package registry (OSV) |
| suse:rmt-server | 1.1.1-3.13.1 · SUSE:Linux Enterprise Module for Server Applications 15 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- A user must open a link or visit a page.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-476 · NULL Pointer DereferenceCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- access.redhat.com/errata/RHSA-2019:1543
- bugs.debian.org/cgi-bin/bugreport.cgi?bug=901817
- bugzilla.redhat.com/show_bug.cgi?id=1595985
- gitlab.gnome.org/GNOME/libxml2/issues/10
- lists.debian.org/debian-lts-announce/2018/09/msg00035.html
- lists.debian.org/debian-lts-announce/2020/09/msg00009.html
- security.netapp.com/advisory/ntap-20190719-0002/
- usn.ubuntu.com/3739-1/
- usn.ubuntu.com/3739-2/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.