MEDIUM
The serializer in html5lib before 0.99999999 might allow remote attackers to conduct cross-site scripting (XSS) attacks by leveraging mishandling of the < (less than) character in attribute values
Published Feb 22, 2017
5.3
MEDIUMCVSS 4.0
EPSS 2.16%
Description
The serializer in html5lib before 0.99999999 might allow remote attackers to conduct cross-site scripting (XSS) attacks by leveraging mishandling of the < (less than) character in attribute values.
Affected products
Remediation
No remediation recorded yet.
Metrics
5.3 MEDIUM GHSA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User Interaction Passive
Vulnerable System Confidentiality None
Vulnerable System Integrity None
Vulnerable System Availability None
Subsequent System Confidentiality Low
Subsequent System Integrity Low
Subsequent System Availability None
No CVSS v3.1 score for this CVE.
6.1 MEDIUM NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Changed
Confidentiality Impact Low
Integrity Impact Low
Availability Impact None
4.3 MEDIUM NVD
AV:N/AC:M/Au:N/C:N/I:P/A:N
Access Vector Network
Access Complexity Medium
Authentication None
Confidentiality Impact None
Integrity Impact Partial
Availability Impact None
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
2.16% 0.02160
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.02160
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (10 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 2.16% (0.02160) | 81.54th | v5 (v2026.06.15) |
| Jun 15, 2026 | 2.14% (0.02141) | 79.60th | v5 (v2026.06.15) |
| Mar 17, 2025 | 0.59% (0.00588) | 67.25th | v4 (v2025.03.14) |
| Dec 12, 2024 | 0.32% (0.00323) | 71.53th | v3 (v2023.03.01) |
| Feb 8, 2024 | 0.32% (0.00323) | 69.88th | v3 (v2023.03.01) |
| Mar 7, 2023 | 0.32% (0.00323) | 65.97th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.32% (0.01319) | 71.27th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.32% (0.01319) | 71.23th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.32% (0.01319) | 69.22th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.32% (0.01319) | 44.98th | v2 (v2022.01.01) |
Weaknesses (1)
References (11)
- http://www.openwall.com/lists/oss-security/2016/12/06/5 mailing-listx_refsource_MLISTMailing ListPatchThird Party Advisory
- http://www.openwall.com/lists/oss-security/2016/12/08/8 mailing-listx_refsource_MLISTMailing ListPatchThird Party Advisory
- http://www.securityfocus.com/bid/95132 vdb-entryx_refsource_BIDThird Party AdvisoryVDB Entry
- https://github.com/advisories/GHSA-v9v9-xffq-rwr4 Advisory
- https://github.com/html5lib/html5lib-python/commit/9b8d8eb5afbc066b7fac9390f5ec75e5e8a7cab7 x_refsource_CONFIRMPatch
- https://github.com/html5lib/html5lib-python/issues/11 x_refsource_CONFIRMVendor Advisory
- https://github.com/html5lib/html5lib-python/issues/12 x_refsource_CONFIRMVendor Advisory
- https://github.com/pypa/advisory-database/tree/main/vulns/html5lib/PYSEC-2017-14.yaml
- https://html5lib.readthedocs.io/en/latest/changes.html#b9 x_refsource_CONFIRMRelease Notes
- https://nvd.nist.gov/vuln/detail/CVE-2016-9909
- https://web.archive.org/web/20161229134056/http://www.securityfocus.com/bid/95132
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner redhat
Published Feb 22, 2017
Updated Aug 6, 2024
Reserved Dec 8, 2016
Link CVE-2016-9909
CISA Vulnrichment
GHSA-V9V9-XFFQ-RWR4 Updated n/a