CriticalCVE-2021-35942

    GNU glibc: Denial of Service (CVE-2021-35942)

    Published Last modified Sources: CVE.org

    What is affected, what to do

    The wordexp function in the GNU C Library (aka glibc) through 2.33 may crash or read arbitrary memory in parse_param (in posix/wordexp.c) when called with an untrusted, crafted pattern, potentially resulting in a denial of service or disclosure of information. This occurs because atoi was used but strtoul should have been used to ensure correct calculations.

    Update GNU glibc to version 2.31.

    Affected
    • GNU glibc lt *..2.31
    • NetApp E-Series SANtricity OS Controller lte 11.0..11.70.1
    • Debian Linux eq 10.0..10.0
    Fixed in
    • GNU glibc 2.31

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

    Metrics

    9.1

    Priority

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

    Source: NVD, CVSS v3

    9.1

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: CVE.org

    2.8 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 86.2

    Show all metrics
    Severity
    Critical
    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
    104.90 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
    9.1 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
    9.1
    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
    2.8 %
    Moderate — model estimates 1-10% 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
    86.2
    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

    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

    The wordexp function in the GNU C Library (aka glibc) through 2.33 may crash or read arbitrary memory in parse_param (in posix/wordexp.c) when called with an untrusted, crafted pattern, potentially resulting in a denial of service or disclosure of information. This occurs because atoi was used but strtoul should have been used to ensure correct calculations.

    Source: cvelistv5, NVD (NIST)

    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
    gnuglibc
    • < 2.31
    • 2.31
    netappactive_iq_unified_manager
    • —
    • —
    netappe-series_santricity_os_controller
    • 11.0 – ≤ 11.70.1
    • —
    netapphci_management_node
    • —
    • —
    netappontap_select_deploy_administration_utility
    • —
    • —
    netappsolidfire
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedMITRE

      Show 18 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html
      Referenceadded
      —
      https://security.gentoo.org/glsa/202208-24
      Referenceadded
      —
      https://security.netapp.com/advisory/ntap-20210827-0005/
      Referenceadded
      —
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011
      Referenceadded
      —
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c
      Referenceadded
      —
      https://sourceware.org/glibc/wiki/Security%20Exceptions
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html
      —
      Referenceremoved
      https://security.gentoo.org/glsa/202208-24
      —
      Referenceremoved
      https://security.netapp.com/advisory/ntap-20210827-0005/
      —
      Referenceremoved
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011
      —
      Referenceremoved
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c
      —
      Referenceremoved
      https://sourceware.org/glibc/wiki/Security%20Exceptions
      —
      Reference typeremoved
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html Types: Mailing List, Third Party Advisory
      —
      Reference typeremoved
      https://security.gentoo.org/glsa/202208-24 Types: Third Party Advisory
      —
      Reference typeremoved
      https://security.netapp.com/advisory/ntap-20210827-0005/ Types: Third Party Advisory
      —
      Reference typeremoved
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011 Types: Issue Tracking, Third Party Advisory
      —
      Reference typeremoved
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c Types: Broken Link
      —
      Reference typeremoved
      https://sourceware.org/glibc/wiki/Security%20Exceptions Types: Not Applicable
      —

      Source identifier: cve@mitre.org

    2. Record modifiedCVE Program

      Show 18 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html
      Referenceadded
      —
      https://security.gentoo.org/glsa/202208-24
      Referenceadded
      —
      https://security.netapp.com/advisory/ntap-20210827-0005/
      Referenceadded
      —
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011
      Referenceadded
      —
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c
      Referenceadded
      —
      https://sourceware.org/glibc/wiki/Security%20Exceptions
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html
      —
      Referenceremoved
      https://security.gentoo.org/glsa/202208-24
      —
      Referenceremoved
      https://security.netapp.com/advisory/ntap-20210827-0005/
      —
      Referenceremoved
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011
      —
      Referenceremoved
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c
      —
      Referenceremoved
      https://sourceware.org/glibc/wiki/Security%20Exceptions
      —
      Reference typeremoved
      https://lists.debian.org/debian-lts-announce/2022/10/msg00021.html Types: Mailing List, Third Party Advisory
      —
      Reference typeremoved
      https://security.gentoo.org/glsa/202208-24 Types: Third Party Advisory
      —
      Reference typeremoved
      https://security.netapp.com/advisory/ntap-20210827-0005/ Types: Third Party Advisory
      —
      Reference typeremoved
      https://sourceware.org/bugzilla/show_bug.cgi?id=28011 Types: Issue Tracking, Third Party Advisory
      —
      Reference typeremoved
      https://sourceware.org/git/?p=glibc.git%3Ba=commit%3Bh=5adda61f62b77384718b4c0d8336ade8f2b4b35c Types: Broken Link
      —
      Reference typeremoved
      https://sourceware.org/glibc/wiki/Security%20Exceptions Types: Not Applicable
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. Record modifiedSiemens ADP

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2021/35xxx/CVE-2021-35942.json">CVE-2021-35942</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-398330.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-831302.html

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

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