Inefficient Regular Expression Complexity Affecting thunderbird package, versions <1:91.8.0-1


0.0
high

Snyk CVSS

    Attack Complexity Low
    Availability High

    Threat Intelligence

    EPSS 0.36% (72nd percentile)
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NVD
7.5 high
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SUSE
4.3 medium
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Red Hat
7.5 high

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  • Snyk ID SNYK-DEBIANUNSTABLE-THUNDERBIRD-2441789
  • published 10 Mar 2022
  • disclosed 8 Mar 2022

How to fix?

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

NVD Description

Note: Versions mentioned in the description apply only to the upstream thunderbird package and not the thunderbird 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.