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Vulnerability details: VCID-3p1d-tfde-6khg
Vulnerability ID VCID-3p1d-tfde-6khg
Aliases CVE-2017-16876
GHSA-98gj-wwxm-cj3h
PYSEC-2017-18
Summary Cross-site scripting (XSS) vulnerability in the _keyify function in mistune.py in Mistune before 0.8.1 allows remote attackers to inject arbitrary web script or HTML by leveraging failure to escape the "key" argument.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.00227 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.0058 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.0058 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
epss 0.0058 https://api.first.org/data/v1/epss?cve=CVE-2017-16876
cvssv3.1 6.1 https://bugzilla.redhat.com/show_bug.cgi?id=1524596
cvssv4 5.1 https://bugzilla.redhat.com/show_bug.cgi?id=1524596
generic_textual MODERATE https://bugzilla.redhat.com/show_bug.cgi?id=1524596
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-98gj-wwxm-cj3h
cvssv3.1 6.1 https://github.com/lepture/mistune
cvssv4 5.1 https://github.com/lepture/mistune
generic_textual MODERATE https://github.com/lepture/mistune
cvssv3.1 6.1 https://github.com/lepture/mistune/blob/master/CHANGES.rst
cvssv4 5.1 https://github.com/lepture/mistune/blob/master/CHANGES.rst
generic_textual MODERATE https://github.com/lepture/mistune/blob/master/CHANGES.rst
cvssv3.1 6.1 https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
cvssv4 5.1 https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
generic_textual MODERATE https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
cvssv3.1 6.1 https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
cvssv4 5.1 https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
generic_textual MODERATE https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
cvssv3.1 6.1 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
cvssv4 5.1 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
generic_textual MODERATE https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
cvssv2 4.3 https://nvd.nist.gov/vuln/detail/CVE-2017-16876
cvssv3 6.1 https://nvd.nist.gov/vuln/detail/CVE-2017-16876
cvssv3.1 6.1 https://nvd.nist.gov/vuln/detail/CVE-2017-16876
cvssv4 5.1 https://nvd.nist.gov/vuln/detail/CVE-2017-16876
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2017-16876
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2017-16876
https://bugzilla.redhat.com/show_bug.cgi?id=1524596
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-16876
https://github.com/advisories/GHSA-98gj-wwxm-cj3h
https://github.com/lepture/mistune
https://github.com/lepture/mistune/blob/master/CHANGES.rst
https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC/
cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:mistune_project:mistune:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:26:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:26:*:*:*:*:*:*:*
CVE-2017-16876 https://nvd.nist.gov/vuln/detail/CVE-2017-16876
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://bugzilla.redhat.com/show_bug.cgi?id=1524596
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://bugzilla.redhat.com/show_bug.cgi?id=1524596
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/lepture/mistune
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://github.com/lepture/mistune
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/lepture/mistune/blob/master/CHANGES.rst
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://github.com/lepture/mistune/blob/master/CHANGES.rst
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://github.com/lepture/mistune/commit/5f06d724bc05580e7f203db2d4a4905fc1127f98
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://github.com/pypa/advisory-database/tree/main/vulns/mistune/PYSEC-2017-18.yaml
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NUR3GMHQBMA3UC4PFMCK6GCLOQC4LQQC
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:M/Au:N/C:N/I:P/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2017-16876
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2017-16876
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2017-16876
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N Found at https://nvd.nist.gov/vuln/detail/CVE-2017-16876
Attack Vector (AV) Attack Complexity (AC) Attack Requirements (AT) Privileges Required (PR) User Interaction (UI) Vulnerable System Impact Confidentiality (VC) Vulnerable System Impact Integrity (VI) Vulnerable System Impact Availability (VA) Subsequent System Impact Confidentiality (SC) Subsequent System Impact Integrity (SI) Subsequent System Impact Availability (SA)

network

adjacent

local

physical

low

high

none

present

none

low

high

none

passive

active

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.45436
EPSS Score 0.00227
Published At April 7, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-04-01T12:41:38.921248+00:00 Pypa Importer Import https://github.com/pypa/advisory-database/blob/main/vulns/mistune/PYSEC-2017-18.yaml 38.0.0