PyPi: Snudown

CVE-2021-41168

Safety vulnerability ID: 42206

This vulnerability was reviewed by experts

The information on this page was manually curated by our Cybersecurity Intelligence Team.

Created at Oct 21, 2021 Updated at Nov 29, 2024
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Advisory

Snudown 1.7.0 includes a fix for CVE-2021-41168: In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown " [reference_name]: https://www.example.com" are inserted into a hash table which was found to have a weak hash function, meaning that an attacker can reliably generate a large number of collisions for it. This makes the hash table vulnerable to a hash-collision DoS attack, a type of algorithmic complexity attack. Further, the hash table allows for duplicate entries resulting in long retrieval times. Proofs of concept and further discussion of the hash collision issue are discussed on the snudown GHSA (https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6).
https://github.com/reddit/snudown/commit/1ac2c130b210539ee1e5d67a7bac93f9d8007c0e

Affected package

snudown

Latest version: 1.0.0

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Affected versions

Fixed versions

Vulnerability changelog

Snudown is a reddit-specific fork of the Sundown Markdown parser used by GitHub, with Python integration added. In affected versions snudown was found to be vulnerable to denial of service attacks to its reference table implementation. References written in markdown ` [reference_name]: https://www.example.com` are inserted into a hash table which was found to have a weak hash function, meaning that an attacker can reliably generate a large number of collisions for it. This makes the hash table vulnerable to a hash-collision DoS attack, a type of algorithmic complexity attack. Further the hash table allowed for duplicate entries resulting in long retrieval times. Proofs of concept and further discussion of the hash collision issue are discussed on the snudown GHSA(https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6). Users are advised to update to version 1.7.0. See CVE-2021-41168.


CONFIRM:https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6: https://github.com/reddit/snudown/security/advisories/GHSA-6gvv-9q92-w5f6
MISC:https://github.com/reddit/snudown/commit/1ac2c130b210539ee1e5d67a7bac93f9d8007c0e: https://github.com/reddit/snudown/commit/1ac2c130b210539ee1e5d67a7bac93f9d8007c0e

Resources

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Severity Details

CVSS Base Score

MEDIUM 6.5

CVSS v3 Details

MEDIUM 6.5
Attack Vector (AV)
NETWORK
Attack Complexity (AC)
LOW
Privileges Required (PR)
LOW
User Interaction (UI)
NONE
Scope (S)
UNCHANGED
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Availability (A)
HIGH

CVSS v2 Details

MEDIUM 4.0
Access Vector (AV)
NETWORK
Access Complexity (AC)
LOW
Authentication (Au)
SINGLE
Confidentiality Impact (C)
NONE
Integrity Impact (I)
NONE
Availability Impact (A)
PARTIAL