HTML Cleaner allows crafted and SVG embedded scripts to pass through
lxml is a library for processing XML and HTML in the Python language. Prior to version 4.6.5, the HTML Cleaner in lxml.html lets certain crafted script content pass through, as well as script content in SVG files embedded using data URIs. Users that employ the HTML cleaner in a security relevant context should upgrade to lxml 4.6.5 to receive a patch. There are no known workarounds available.
- BDU:2022-00756
- GHSA-55x5-fj6c-h6m8
- ALSA-2022:1763
- ALSA-2022:1764
- ALSA-2022:1821
- ALSA-2022:1932
- DLA-2871-1
- DSA-5043-1
- openSUSE-SU-2022:0803-1
- PYSEC-2021-852
- RHSA-2022:1664
- RHSA-2022:1763
- RHSA-2022:1764
- RHSA-2022:1821
- RHSA-2022:1932
- RHSA-2022:5498
- RLSA-2022:1763
- RLSA-2022:1764
- RLSA-2022:1821
- RLSA-2022:1932
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; 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 help- Published
- Dec 13, 2021
- Updated
- Jun 17, 2026
- EPSS
- 2.5% · 84th percentile
- CWE
- CWE-74
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Report tools
Action score
29
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 2.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.1
- CNA · GitHub_M
- 8.2
- 1.1 point gap
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| lxml | lxml | cpe:2.3:a:lxml:lxml |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | solidfire | cpe:2.3:a:netapp:solidfire |
| netapp | solidfire enterprise sds | cpe:2.3:a:netapp:solidfire_enterprise_sds |
| netapp | hci storage node firmware | cpe:2.3:o:netapp:hci_storage_node_firmware |
| netapp | hci storage node | cpe:2.3:h:netapp:hci_storage_node |
| oracle | communications cloud native core binding support function | cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function |
| oracle | communications cloud native core network exposure function | cpe:2.3:a:oracle:communications_cloud_native_core_network_exposure_function |
| oracle | communications cloud native core policy | cpe:2.3:a:oracle:communications_cloud_native_core_policy |
| oracle | http server | cpe:2.3:a:oracle:http_server |
| oracle | zfs storage appliance kit | cpe:2.3:a:oracle:zfs_storage_appliance_kit |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux11.0
- debian debian linux9.0
- fedoraproject fedora34
- fedoraproject fedora35
- lxml lxmlbefore 4.6.5
- netapp hci storage node firmwareall versions
- netapp solidfireall versions
- netapp solidfire enterprise sdsall versions
- oracle communications cloud native core binding support function22.1.3
- oracle communications cloud native core network exposure function22.1.1
- oracle communications cloud native core policy22.2.0
- oracle http server12.2.1.3.0
- oracle http server12.2.1.4.0
- oracle zfs storage appliance kit8.8
Versions reported by the vendor
Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.
lxml lxml
- < 4.6.5affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | babel | before 2.5.1-10.module_el8.6.0+2781+fed64c13 | 2.5.1-10.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python-nose-docs | before 1.3.7-31.module_el8.5.0+2569+5c5719bc | 1.3.7-31.module_el8.5.0+2569+5c5719bc |
| AlmaLinux:8 | python-nose-docs | before 1.3.7-31.module_el8.6.0+2781+fed64c13 | 1.3.7-31.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python-psycopg2-doc | before 2.7.5-7.module_el8.6.0+2781+fed64c13 | 2.7.5-7.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python-sqlalchemy-doc | before 1.3.2-2.module_el8.6.0+2781+fed64c13 | 1.3.2-2.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python-sqlalchemy-doc | before 1.3.2-2.module_el8.5.0+2569+5c5719bc | 1.3.2-2.module_el8.5.0+2569+5c5719bc |
| AlmaLinux:8 | python2 | before 2.7.18-10.module_el8.6.0+2781+fed64c13.alma | 2.7.18-10.module_el8.6.0+2781+fed64c13.alma |
| AlmaLinux:8 | python2-attrs | before 17.4.0-10.module_el8.6.0+2781+fed64c13 | 17.4.0-10.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-babel | before 2.5.1-10.module_el8.6.0+2781+fed64c13 | 2.5.1-10.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-backports | before 1.0-16.module_el8.6.0+2781+fed64c13 | 1.0-16.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-backports-ssl_match_hostname | before 3.5.0.1-12.module_el8.6.0+2781+fed64c13 | 3.5.0.1-12.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-bson | before 3.7.0-1.module_el8.6.0+2781+fed64c13 | 3.7.0-1.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-chardet | before 3.0.4-10.module_el8.6.0+2781+fed64c13 | 3.0.4-10.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-coverage | before 4.5.1-4.module_el8.6.0+2781+fed64c13 | 4.5.1-4.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-Cython | before 0.28.1-7.module_el8.6.0+2781+fed64c13 | 0.28.1-7.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-debug | before 2.7.18-10.module_el8.6.0+2781+fed64c13.alma | 2.7.18-10.module_el8.6.0+2781+fed64c13.alma |
| AlmaLinux:8 | python2-devel | before 2.7.18-10.module_el8.6.0+2781+fed64c13.alma | 2.7.18-10.module_el8.6.0+2781+fed64c13.alma |
| AlmaLinux:8 | python2-dns | before 1.15.0-10.module_el8.6.0+2781+fed64c13 | 1.15.0-10.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-docs | before 2.7.16-2.module_el8.6.0+2781+fed64c13 | 2.7.16-2.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-docs-info | before 2.7.16-2.module_el8.6.0+2781+fed64c13 | 2.7.16-2.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-docutils | before 0.14-12.module_el8.6.0+2781+fed64c13 | 0.14-12.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-funcsigs | before 1.0.2-13.module_el8.6.0+2781+fed64c13 | 1.0.2-13.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-idna | before 2.5-7.module_el8.6.0+2781+fed64c13 | 2.5-7.module_el8.6.0+2781+fed64c13 |
| AlmaLinux:8 | python2-ipaddress | before 1.0.18-6.module_el8.6.0+2781+fed64c13 | 1.0.18-6.module_el8.6.0+2781+fed64c13 |
+96
Same product
lxml: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-49825lxml: javascript: URL bypass in Cleaner via xlink:href32Monitor
- CVE-2022-2309NULL Pointer Dereference in lxml/lxml31Monitor
- CVE-2026-41066lxml: Default configuration of iterparse() and ETCompatXMLParser() allows XXE to local files30Monitor
- CVE-2014-3146Incomplete blacklist vulnerability in the lxml.html.clean module in lxml before 3.3.5 allows remote attackers to conduct cross-site scriptin26Monitor
- CVE-2021-28957An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3.25Monitor
- CVE-2020-27783A XSS vulnerability was discovered in python-lxml's clean module.25Monitor
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 |
|---|---|---|
| almalinux:python39 | 3.9.7-1.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-attrs | 20.3.0-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-cffi | 1.14.3-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-chardet | 3.0.4-19.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-cryptography | 3.3.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-Cython | 0.29.21-5.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-debug | 3.9.7-1.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-devel | 3.9.7-1.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-idle | 3.9.7-1.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-idna | 2.10-3.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-iniconfig | 1.1.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:python39-PyMySQL | 0.10.1-2.module_el8.6.0+2780+a40f65e1 · AlmaLinux:8 | Package registry (OSV) |
| alpine:py3-lxml | 4.6.5-r0 · Alpine:v3.16 | Package registry (OSV) |
| debian:lxml | 4.7.1-1 · Debian:12 | Package registry (OSV) |
| opensuse:python-lxml | 4.7.1-3.7.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| PyPI:lxml | 4.6.5 | Package registry (OSV) |
| red hat:mod_wsgi | 0:4.7.1-4.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:numpy | 0:1.19.4-3.module+el8.5.0+12204+54860423 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:numpy-debugsource | 0:1.19.4-3.module+el8.5.0+12204+54860423 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-cffi | 0:1.14.3-2.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-cffi-debugsource | 0:1.14.3-2.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-chardet | 0:3.0.4-19.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-cryptography | 0:3.3.1-2.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:python-PyMySQL | 0:0.10.1-2.module+el8.4.0+9822+20bf1249 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:PyYAML | 0:5.4.1-1.module+el8.5.0+10613+59a13ec4 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:PyYAML-debugsource | 0:5.4.1-1.module+el8.5.0+10613+59a13ec4 · Red Hat:enterprise_linux:8::appstream | Package registry (OSV) |
| red hat:rh-python38-python-lxml | 0:4.4.1-8.el7 · Red Hat:rhel_software_collections:3::el7 | Package registry (OSV) |
| red hat:rh-python38-python-lxml-debuginfo | 0:4.4.1-8.el7 · Red Hat:rhel_software_collections:3::el7 | Package registry (OSV) |
| rocky linux:Cython | 0:0.29.21-5.module+el8.4.0+574+843c4898 · Rocky Linux:8 | Package registry (OSV) |
| rocky linux:mod_wsgi | 0:4.7.1-4.module+el8.4.0+574+843c4898 · Rocky Linux:8 | Package registry (OSV) |
+22
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.
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
- low · data can be read
- Integrity
- low · data or configuration can be modified
- Availability
- low · the service can be disrupted
Impact can extend beyond the vulnerable component (scope changes).
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- Low
Weakness class (CWE)
CWE-74 · Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- HTTP Request SplittingCAPEC-105likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- Format String InjectionCAPEC-135likelihood: High · High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/lxml/lxml/commit/12fa9669007180a7bb87d990c375cf91ca5b664a
- github.com/lxml/lxml/commit/a3eacbc0dcf1de1c822ec29fb7d090a4b1712a9c#diff-59130575b4fb2932c957db2922977d7d89afb0b2085357db1a14615a2fcad776
- github.com/lxml/lxml/commit/f2330237440df7e8f39c3ad1b1aa8852be3b27c0
- github.com/lxml/lxml/security/advisories/GHSA-55x5-fj6c-h6m8
- lists.debian.org/debian-lts-announce/2021/12/msg00037.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TUIS2KE3HZ2AAQKXFLTJFZPP2IFHJTC7/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/V2XMOM5PFT6U5AAXY6EFNT5JZCKKHK2V/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WZGNET2A4WGLSUXLBFYKNC5PXHQMI3I7/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZQ4SPKJX3RRJK4UWA6FXCRHD2TVRQI44/
- security.gentoo.org/glsa/202208-06
- security.netapp.com/advisory/ntap-20220107-0005/
- www.debian.org/security/2022/dsa-5043
- www.oracle.com/security-alerts/cpuapr2022.html
- www.oracle.com/security-alerts/cpujul2022.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.