CVE-2016-9909
CVE-2016-9909 is a medium-severity vulnerability in Html5lib with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.
Key facts
- Severity: Medium (CVSS 3.x base score 6.1)
- CVSS v2: 4.3
- EPSS exploit prediction: 2% (80th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-79
- Affected product: Html5lib
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2016-9909?
- 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.
- How severe is CVE-2016-9909?
- CVE-2016-9909 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
- Is CVE-2016-9909 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (80th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2016-9909?
- CVE-2016-9909 affects Html5lib. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2016-9909?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2016-9909 published?
- CVE-2016-9909 was published on 2017-02-22 and last updated on 2026-06-17.
References
- http://www.openwall.com/lists/oss-security/2016/12/06/5
- http://www.openwall.com/lists/oss-security/2016/12/08/8
- http://www.securityfocus.com/bid/95132
- https://github.com/html5lib/html5lib-python/commit/9b8d8eb5afbc066b7fac9390f5ec75e5e8a7cab7
- https://github.com/html5lib/html5lib-python/issues/11
- https://github.com/html5lib/html5lib-python/issues/12
- https://html5lib.readthedocs.io/en/latest/changes.html#b9
Affected products (1)
- cpe:2.3:a:html5lib:html5lib:*:1.0b8:*:*:*:*:*:*
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- CVE-2016-9910 — Medium (CVSS 6.1): The serializer in html5lib before 0.99999999 might allow remote attackers to conduct cross-site scripting (XSS) attacks…
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