Vulnerability feed

Executive summary

The Mistune Markdown parser, before version 3.3.0, has a flaw that lets attackers read arbitrary files on the server. The advisory also says it can enable cross-site scripting, and it rates the issue high severity with a CVSS score of 8.7.

Technical summary

The flaw is a path traversal (CWE-22) in the Include directive, where ../ sequences in include paths let an attacker read arbitrary files. The CVSS v4 vector given is AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N, which indicates network attack with no privileges or user interaction and high confidentiality impact. The advisory also states that unescaped error messages and included file contents allow XSS even when escape=True is set. The fixed version is stated as 3.3.0, and the affected range is listed as mistune >= 0, < 3.3.0. No workarounds, detection guidance, or exploitation-in-the-wild information is stated in the advisory.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from vulncheck.com/advisories/mistune-before…ia-include-directive

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

Mistune, a Python Markdown library, has a path traversal flaw in its opt-in Include directive that lets an attacker read local files on the server when an application renders attacker-supplied Markdown files with that directive enabled. The advisory rates it Moderate with a CVSS v3.1 base score of 6.5, and the fix is to upgrade to version 3.3.0.

Technical summary

The flaw is CWE-22 path traversal in the Include directive, where relative or absolute include paths are resolved against the source file's directory without a root restriction, so included files can be read and embedded in HTML output without escaping. Exploitation requires the application to enable RSTDirective with Include and to render attacker-controlled Markdown files through Markdown.read(path); the advisory rates the attack vector as network, complexity low, no privileges, user interaction required, with high confidentiality impact. Affected version is stated as 3.2.0 and patched version as 3.3.0, and the advisory says mistune before 3.3.0 is affected. No workaround is stated beyond the integration pattern being risky, and no detection guidance is stated. The advisory states no CVE ID is assigned, and exploitation in the wild is not stated.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-jhcm-5rpf-j3wv

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

Passive

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

lepturelepture mistune

Executive summary

Mistune, a Python Markdown renderer, contains a path traversal flaw in its RST include directive that lets an attacker read arbitrary files on the server that the rendering process can access. The advisory rates it High with a CVSS base score of 8.6, and the fix is to upgrade to version 3.3.0 or later.

Technical summary

The flaw is a path traversal (CWE-22 and CWE-73) in the include directive plugin, where the directive argument is joined to the source directory without containment checks, so absolute paths or ../ sequences read any file the process can open. The attacker needs only to submit markdown to an application that renders it with the Include directive enabled and state.env['__file__'] set; no authentication or user interaction is stated, and the CVSS vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N. With escape=False, including an attacker-supplied .html file can also yield stored XSS. Affected versions are stated as 3.2.1 and earlier (<= 3.2.1), with the patched version 3.3.0. The advisory suggests a realpath and commonpath containment check, but it does not state a workaround other than that fix, and no detection guidance or evidence of in-the-wild exploitation is stated.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-9jjx-3hq3-hx4j

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

The advisory says the Mistune Python Markdown library, versions 3.2.1 and earlier, can be made to use excessive CPU by a small crafted Markdown input, causing a denial of service for any service that renders untrusted Markdown. It rates the issue High with a CVSS 3.1 base score of 7.5, and the fix is to upgrade to version 3.3.0.

Technical summary

This is an algorithmic complexity denial of service in the inline link parser, where long runs of unmatched '[' characters cause quadratic time parsing, tied to CWE-407 and CWE-1333. The attack is network-reachable and needs no authentication or user interaction, using a small Markdown payload such as about 16 KB of '[' characters, which the advisory says takes over 30 seconds to process. Affected versions are stated as <= 3.2.1 and the patched version is 3.3.0. The advisory describes two possible workarounds (capping tracked open brackets or a delimiter-stack rewrite), but these are suggested fixes rather than stated workarounds for deployed systems, and no detection guidance is stated. No CVE ID is listed (the advisory says 'No known CVE'), and no evidence of exploitation in the wild is stated.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-xrpv-r66x-8p7j

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

The mistune Python Markdown library, versions from 3.2.1 up to but not including 3.3.0, contains a CSS injection flaw in its Figure directive. The advisory rates it Moderate severity, and the vendor's recommended fix is to upgrade to version 3.3.0.

Technical summary

The flaw is CSS injection (CWE-94 and CWE-1287) in the figwidth option of the Figure directive, which is concatenated unvalidated into a style attribute of the rendered figure tag. An attacker who can supply markdown input can add CSS declarations, such as a url() background that triggers outbound requests for data exfiltration. The advisory's CVSS v3 base vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N, and it states that the affected versions are 5 3.2.1 and below, with 3.3.0 as the patched version. The advisory describes a suggested code fix that applies the existing length regex to figwidth, but it does not state a workaround for users who cannot upgrade. Whether exploitation in the wild has occurred is not stated, and no CVE ID is listed in the advisory.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-xmwc-wjpr-q378

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

Passive

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

The Mistune Python Markdown library, versions up to and including 3.2.1, can be made to output unescaped HTML from an included file when the Include directive is used with escape=False. An attacker who can place a crafted .html file where the rendering process can read it could cause cross-site scripting in pages that render their Markdown. The advisory rates the severity as moderate (CVSS 3.1 base score 6.1), and the fix is to upgrade to version 3.3.0.

Technical summary

The flaw is cross-site scripting (CWE-79, with CWE-95 also listed) caused by the Include directive returning .html, .xhtml, and .htm file contents as raw block_html tokens, which the HTML renderer passes through unescaped when escape=False. Exploitation requires the application to use escape=False with the Include directive enabled, and an attacker who can write a .html file to a path the rendering process can read, then reference it from attacker-controlled Markdown; the advisory notes the path-traversal issue in the Include directive makes this easier. Affected versions are stated as less than or equal to 3.2.1, and the patched version is 3.3.0. The advisory describes a suggested code change that emits included HTML as a code block instead, and recommends pairing it with path containment; no workaround beyond that and the upgrade is explicitly stated. The advisory does not state whether exploitation has been observed in the wild, and no detection guidance is given beyond the proof of concept.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-96vr-jm8v-g22j

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

Passive

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

The Mistune Python Markdown library, versions 3.0.0 through 3.2.1, is affected by a denial of service flaw. A single crafted Markdown input with many nested square brackets can consume large amounts of server CPU time and can exhaust resources under a few concurrent requests. The advisory rates it High (7.5) and the fix is to upgrade to Mistune 3.3.0.

Technical summary

The flaw is an algorithmic complexity issue (CWE-1333, inefficient regular expression complexity) in the parse_link_text function in src/mistune/helpers.py, where scanning for bracket characters is quadratic in input size. An unauthenticated remote attacker can trigger it with a single crafted Markdown request containing deeply nested brackets, and the advisory reports about 72.91 seconds for n=16,000 on version 3.2.1. The advisory states the affected range as >=3.0.0 and <=3.2.1 and the patched version as 3.3.0, and the CVSS v3.1 vector is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. No workaround is stated, and no detection guidance is stated. The advisory also notes that no CVE ID is known for it, and it does not state whether the flaw is exploited in the wild.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-3q64-rw38-243v

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

lepturelepture mistune

Executive summary

A flaw in the mistune Markdown library for Python lets an unauthenticated attacker send a short string of unbalanced square brackets that makes rendering consume large amounts of CPU, which can tie up a server worker for a long time. The advisory rates it High, with a proposed CVSS 3.1 score of 7.5 that the maintainer has not yet confirmed. The advisory shows the issue in version 3.2.1 and the fix is to upgrade to version 3.3.0, which the advisory lists as the patched version.

Technical summary

This is an algorithmic complexity flaw (CWE-1333, leading to CWE-400) in the inline link parser's parse_link_text function, where an input of many unmatched opening brackets causes quadratic-time scanning. The attack vector is network, requires no privileges or user interaction, and only needs the attacker to supply Markdown that the application renders; the advisory says the default configuration and escape=True safe mode are both affected. Affected versions are listed as >= 3.0.0 and <= 3.2.1, with the patched version 3.3.0. The advisory describes a fix that bounds the fallback scan, but it does not state a workaround for users who cannot upgrade. Detection guidance is not stated, and no CVE identifier is given in the advisory.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-x2gr-6qf2-fc9x

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

leptureMistunelepture mistuneMistune

Executive summary

Mistune, a Python Markdown library, has a flaw that lets an attacker with control over Markdown input make the server spend excessive time rendering it, causing denial of service. The advisory rates it as moderate severity, and the fix is to upgrade to version 3.3.0.

Technical summary

The flaw is an inefficient algorithmic complexity issue (CWE-407) in parse_link_text, which rescans forward for each unmatched opening square bracket, giving quadratic runtime on inputs made of many unbalanced brackets. The attacker only needs to supply Markdown rendered by mistune.html(), with no authentication stated. Affected versions are 3.2.0 and 3.2.1 and the current main branch, and the patched version is 3.3.0. The advisory reports timing data (about 25 KB of brackets exceeding 15 seconds on one test machine) but does not state a CVE ID, a CVSS score, or any workaround. Detection guidance such as specific signatures or log indicators is not stated, though the advisory includes a proof-of-concept script and suggests capping the forward scan length as a code-level fix.

Summaries are generated by AI from the linked advisory text. Confirm versions and fixes at the source.

Summarized from github.com/lepture/mistune/security/adv…/GHSA-f32h-38gf-rg5r

Impact if exploited

How it is exploited

Attack vector

Network

Attack complexity

Low

Attack requirements

None

Privileges required

None

User interaction

None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affects

lepturelepture mistune