HighCVE-2022-24713

    Regular expression denial of service in Rust's regex crate (CVE-2022-24713)

    Published Sources: CVE.org, OSV, Debian, Msrc Update Guide, SUSE

    What is affected, what to do

    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.

    Update Rust Regex to version 1.5.5.

    Affected
    • Rust Regex lt *..1.5.5
    Fixed in
    • Rust Regex 1.5.5

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.5

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org, OSV, Debian, Msrc Update Guide, SUSE

    14.5 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 96.6

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    112.73 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.5 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.5
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    14.5 %
    Elevated — model estimates 10-50% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    96.6
    Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · automatable · Technical impact: partial
    Source: CISA Vulnrichment, as of 23 April 2025
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-400

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    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.

    Source: NVD (NIST), cvelistv5, OSV (Open Source Vulnerabilities), Debian Security Advisories, Microsoft Security Update Guide, suse_csaf

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    rust-langregex
    • < 1.5.5
    • < 1.5.5
    • 1.5.5
    • 1.5.5
    crates.ioregex
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux11.0
    Linuxdebiandebian_linux9.0
    Linuxdebianfirefox-esrbullseye
    Linuxdebianfirefox-esrbuster
    Linuxdebianthunderbirdbullseye
    Linuxdebianthunderbirdbuster
    Otherfedoraprojectfedora34
    Otherfedoraprojectfedora35
    Otherfedoraprojectfedora36

    Weakness classes (CWE)

    • CWE-400Uncontrolled Resource Consumption

      Class

      The product does not properly control the allocation and maintenance of a limited resource.

      Entry at MITRE CWE-400

    References & sources

    • crates.iocrates/regexpackage
    • rustsec.orgadvisories/RUSTSEC-2022-0013.htmladvisory
    • groups.google.comg/rustlang-security-announcements/c/NcNNL1Jq7Ywweb, x_refsource_MISC, Third-party advisory
    • github.comrust-lang/regex/security/advisories/GHSA-m5pq-gvj9-9vr8x_refsource_CONFIRM, Third-party advisory
    • github.comrust-lang/regex/commit/ae70b41d4f46641dbc45c7a4f87954aea356283ex_refsource_MISC, Patch, Third-party advisory
    • lists.fedoraproject.orgFEDORA-2022-ceb3e03c5eVendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2022-8436ac4c39Vendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2022-d20d44ba98Vendor advisory, x_refsource_FEDORA
    • lists.debian.org[debian-lts-announce] 20220407 [SECURITY] [DLA 2971-1] firefox-esr security updateMailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • debian.orgDSA-5113Vendor advisory, x_refsource_DEBIAN, Third-party advisory
    • lists.debian.org[debian-lts-announce] 20220411 [SECURITY] [DLA 2978-1] thunderbird security updateMailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • debian.orgDSA-5118Vendor advisory, x_refsource_DEBIAN, Third-party advisory
    • security.gentoo.orgGLSA-202208-08Vendor advisory, x_refsource_GENTOO, Third-party advisory
    • security.gentoo.orgGLSA-202208-14Vendor advisory, x_refsource_GENTOO, Third-party advisory
    • NVD (NIST)vuln/detail/CVE-2022-24713advisory
    • github.comrust-lang/regexweb
    • lists.fedoraproject.orgarchives/list/package-announce@lists.fedoraproject.org/message/…web
    • lists.fedoraproject.orgarchives/list/package-announce@lists.fedoraproject.org/message/…web
    • lists.fedoraproject.orgarchives/list/package-announce@lists.fedoraproject.org/message/…web
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