HighCVE-2019-11478

    Linux kernel: Allocation of Resources Without Limits or Throttling (CVE-2019-11478)

    Published Sources: CVE.org

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    What is affected, what to do

    Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service.

    An exploit is publicly available. Update Linux kernel to version 4.4.182, Linux kernel to version 4.9.182, Linux kernel to version 4.14.127.

    Affected
    • Linux kernel lt 4.4..4.4.182
    • Linux kernel lt 4.9..4.9.182
    • Linux kernel lt 4.14..4.14.127
    • Linux kernel lt 4.19..4.19.52
    • Linux kernel lt 5.1..5.1.11
    Fixed in
    • Linux kernel 4.4.182
    • Linux kernel 4.9.182
    • Linux kernel 4.14.127
    • Linux kernel 4.19.52
    • Linux kernel 5.1.11

    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

    5.3

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org

    94.7 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.86

    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
    106.28 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
    PoC (publicly reported)
    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
    5.3
    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
    94.7 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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
    99.86
    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
    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-770

    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

    Jonathan Looney discovered that the TCP retransmission queue implementation in tcp_fragment in the Linux kernel could be fragmented when handling certain TCP Selective Acknowledgment (SACK) sequences. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commit f070ef2ac66716357066b683fb0baf55f8191a2e.

    Source: NVD (NIST), cvelistv5

    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
    LinuxLinux kernel
    • 4.14 – < 4.14.127
    • 5.1 – < 5.1.11
    • 4.9 – < 4.9.182
    • 4.19 – < 4.19.52
    • 4.4 – < 4.4.182
    • 4.14.127
    • 5.1.11
    • 4.9.182
    • 4.19.52
    • 4.4.182
    f5big-ip_access_policy_manager
    • 14.0.0 – ≤ 14.1.0
    • 11.5.2 – ≤ 11.6.4
    • 12.1.0 – ≤ 12.1.4
    • 15.0.0
    • 13.1.0 – ≤ 13.1.1
    • —
    • —
    • —
    • —
    • —
    f5big-ip_advanced_firewall_manager
    • 11.5.2 – ≤ 11.6.4
    • 12.1.0 – ≤ 12.1.4
    • 15.0.0
    • 14.0.0 – ≤ 14.1.0
    • 13.1.0 – ≤ 13.1.1
    • —
    • —
    • —
    • —
    • —
    f5big-ip_analytics
    • 15.0.0
    • 11.5.2 – ≤ 11.6.4
    • 13.1.0 – ≤ 13.1.1
    • 14.0.0 – ≤ 14.1.0
    • 12.1.0 – ≤ 12.1.4
    • —
    • —
    • —
    • —
    • —
    f5big-ip_application_acceleration_manager
    • 13.1.0 – ≤ 13.1.1
    • 12.1.0 – ≤ 12.1.4
    • 11.5.2 – ≤ 11.6.4
    • 14.0.0 – ≤ 14.1.0
    • 15.0.0
    • —
    • —
    • —
    • —
    • —
    f5big-ip_application_security_manager
    • 12.1.0 – ≤ 12.1.4
    • 15.0.0
    • 11.5.2 – ≤ 11.6.4
    • 14.0.0 – ≤ 14.1.0
    • 13.1.0 – ≤ 13.1.1
    • —
    • —
    • —
    • —
    • —
    f5big-ip_domain_name_system
    • 13.1.0 – ≤ 13.1.1
    • 12.1.0 – ≤ 12.1.4
    • 11.5.2 – ≤ 11.6.4
    • 14.0.0 – ≤ 14.1.0
    • 15.0.0
    • —
    • —
    • —
    • —
    • —
    f5big-ip_edge_gateway
    • 12.1.0 – ≤ 12.1.4
    • 11.5.2 – ≤ 11.6.4
    • 14.0.0 – ≤ 14.1.0
    • 13.1.0 – ≤ 13.1.1
    • 15.0.0
    • —
    • —
    • —
    • —
    • —
    f5big-ip_fraud_protection_service
    • 11.5.2 – ≤ 11.6.4
    • 14.0.0 – ≤ 14.1.0
    • 12.1.0 – ≤ 12.1.4
    • 13.1.0 – ≤ 13.1.1
    • 15.0.0
    • —
    • —
    • —
    • —
    • —
    f5big-ip_global_traffic_manager
    • 14.0.0 – ≤ 14.1.0
    • 15.0.0
    • 11.5.2 – ≤ 11.6.4
    • —
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxredhatenterprise_linux5.0
    Linuxredhatenterprise_linux6.0
    Linuxredhatenterprise_linux7.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux_aus6.5
    Linuxredhatenterprise_linux_aus6.6
    Linuxredhatenterprise_linux_eus7.4
    Linuxredhatenterprise_linux_eus7.5
    Linuxredhatenterprise_mrg2.0
    Linuxlinuxlinux_kernel—
    Linuxcanonicalubuntu_linux12.04
    Linuxcanonicalubuntu_linux14.04
    Linuxcanonicalubuntu_linux16.04
    Linuxcanonicalubuntu_linux18.04
    Linuxcanonicalubuntu_linux18.10
    Linuxcanonicalubuntu_linux19.04

    Weakness classes (CWE)

    • CWE-770Allocation of Resources Without Limits or Throttling

      Base

      The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

      Entry at MITRE CWE-770

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Packet StormKernel Live Patch Security Notice LSN 0052 1 (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormKernel Live Patch Security Notice LSN 0055 1 (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormKernel Live Patch Security Notice LSN 0058 1 (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • kb.cert.orgVU#905115Third-party advisory, x_refsource_CERT-VN
    • access.redhat.comRHSA-2019:1594Vendor advisory, x_refsource_REDHAT
    • access.redhat.comRHSA-2019:1602Vendor advisory, x_refsource_REDHAT
    • openwall.com[oss-security] 20190628 Re: linux-distros membership application - MicrosoftMailing list, x_refsource_MLIST
    • openwall.com[oss-security] 20190706 Re: linux-distros membership application - MicrosoftMailing list, x_refsource_MLIST
    • openwall.com[oss-security] 20190706 Re: linux-distros membership application - MicrosoftMailing list, x_refsource_MLIST
    • access.redhat.comRHSA-2019:1699Vendor advisory, x_refsource_REDHAT
    • seclists.org20190722 [SECURITY] [DSA 4484-1] linux security updateMailing list, x_refsource_BUGTRAQ
    • openwall.com[oss-security] 20191023 Membership application for linux-distros - VMwareMailing list, x_refsource_MLIST
    • openwall.com[oss-security] 20191029 Re: Membership application for linux-distros - VMwareMailing list, x_refsource_MLIST
    • oracle.comsecurity-alerts/cpujan2020.htmlx_refsource_MISC
    • oracle.comsecurity-alerts/cpuoct2020.htmlx_refsource_MISC
    • github.comNetflix/security-bulletins/blob/master/advisories/third-party/2…x_refsource_MISC, Patch, Third-party advisory
    • wiki.ubuntu.comSecurityTeam/KnowledgeBase/SACKPanicx_refsource_MISC, Mitigation, Third-party advisory
    • access.redhat.comsecurity/vulnerabilities/tcpsackx_refsource_MISC, Third-party advisory
    • packetstormsecurity.comfiles/153346/Kernel-Live-Patch-Security-Notice-LSN-0052-1.htmlx_refsource_MISC, Third-party advisory, Vulnerability database
    • kb.pulsesecure.netarticles/Pulse_Security_Advisories/SA44193x_refsource_CONFIRM, Third-party advisory
    • synology.comsecurity/advisory/Synology_SA_19_28x_refsource_CONFIRM
    • security.netapp.comadvisory/ntap-20190625-0001x_refsource_CONFIRM
    • kc.mcafee.comcorporate/index?page=content&id=SB10287x_refsource_CONFIRM
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