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Reachable Assertion in rulex

Moderate severity GitHub Reviewed Published Jun 21, 2022 in pomsky-lang/pomsky • Updated Jan 27, 2023

Package

cargo rulex (Rust)

Affected versions

< 0.4.3

Patched versions

0.4.3

Description

Impact

When parsing untrusted rulex expressions, rulex may crash, possibly enabling a Denial of Service attack. This happens when the expression contains a multi-byte UTF-8 code point in a string literal or after a backslash, because rulex tries to slice into the code point and panics as a result.

This is a security concern for you, if

  • your service parses untrusted rulex expressions (expressions provided by an untrusted user), and
  • your service becomes unavailable when the thread running rulex panics.

Patches

The crashes are fixed in version 0.4.3. Affected users are advised to update to this version.

Workarounds

You can use catch_unwind to recover from panics.

For more information

If you have any questions or comments about this advisory:

Credits

Credit for finding these bugs goes to

References

@Aloso Aloso published to pomsky-lang/pomsky Jun 21, 2022
Published to the GitHub Advisory Database Jun 21, 2022
Reviewed Jun 21, 2022
Published by the National Vulnerability Database Jun 27, 2022
Last updated Jan 27, 2023

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.073%
(34th percentile)

Weaknesses

CVE ID

CVE-2022-31100

GHSA ID

GHSA-8v9w-p43c-r885

Source code

Credits

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