Inefficient Regular Expression Complexity Affecting firefox-esr package, versions <91.8.0esr-1


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.4% (75th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-FIREFOXESR-2441177
  • published10 Mar 2022
  • disclosed8 Mar 2022

Introduced: 8 Mar 2022

CVE-2022-24713  (opens in a new tab)
CWE-1333  (opens in a new tab)

How to fix?

Upgrade Debian:unstable firefox-esr to version 91.8.0esr-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

regex is an implementation of regular expressions for the Rust language. The regex crate features built-in mitigations to prevent denial of service attacks caused by untrusted regexes, or untrusted input matched by trusted regexes. Those (tunable) mitigations already provide sane defaults to prevent attacks. This guarantee is documented and it's considered part of the crate's API. Unfortunately a bug was discovered in the mitigations designed to prevent untrusted regexes to take an arbitrary amount of time during parsing, and it's possible to craft regexes that bypass such mitigations. This makes it possible to perform denial of service attacks by sending specially crafted regexes to services accepting user-controlled, untrusted regexes. All versions of the regex crate before or equal to 1.5.4 are affected by this issue. The fix is include starting from regex 1.5.5. All users accepting user-controlled regexes are recommended to upgrade immediately to the latest version of the regex crate. Unfortunately there is no fixed set of problematic regexes, as there are practically infinite regexes that could be crafted to exploit this vulnerability. Because of this, it us not recommend to deny known problematic regexes.

CVSS Scores

version 3.1