CriticalCVE-2019-13272

    Linux Kernel Improper Privilege Management Vulnerability (CVE-2019-13272)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to create a ptrace relationship, which allows local users to obtain root access by leveraging certain scenarios with a parent-child process relationship, where a parent drops privileges and calls execve (potentially allowing control by an attacker). One contributing factor is an object lifetime issue (which can also cause a panic).

    The vulnerability is being actively exploited; treat it as a priority. Update Linux Kernel to version 3.16.71, Linux Kernel to version 4.2, Linux Kernel to version 4.4.185. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Linux Kernel lt 3.16.52..3.16.71
    • Linux Kernel lt 4.1.39..4.2
    • Linux Kernel lt 4.4.40..4.4.185
    • Linux Kernel lt 4.8.16..4.9
    • Linux Kernel lt 4.9.1..4.9.185
    • Linux Kernel lt 4.10..4.14.133
    • Linux Kernel lt 4.15..4.19.58
    • Linux Kernel lt 4.20..5.1.17
    • Debian Linux eq 8.0..8.0
    • Debian Linux eq 9.0..9.0
    • Debian Linux eq 10.0..10.0
    • Fedora eq 29..29
    • Canonical Ubuntu Linux eq 16.04..16.04
    • Canonical Ubuntu Linux eq 18.04..18.04
    • Canonical Ubuntu Linux eq 19.04..19.04
    • Redhat Enterprise Linux eq 7.0..7.0
    • Redhat Enterprise Linux eq 8.0..8.0
    • Red Hat Enterprise Linux For Arm 64 eq 7.0_aarch64..7.0_aarch64
    • Red Hat Enterprise Linux For IBM Z Systems eq 7.0_s390x..7.0_s390x
    • Red Hat Enterprise Linux For Real Time eq 8..8
    • Red Hat Enterprise Linux For Real Time For NFV eq 8.0..8.0
    • Red Hat Enterprise Linux For Real Time For Nfv Tus eq 8.2..8.2
    • Red Hat Enterprise Linux For Real Time For Nfv Tus eq 8.4..8.4
    • Red Hat Enterprise Linux For Real Time For Nfv Tus eq 8.6..8.6
    • Red Hat Enterprise Linux For Real Time For Nfv Tus eq 8.8..8.8
    • Red Hat Enterprise Linux For Real Time Tus eq 8.2..8.2
    • Red Hat Enterprise Linux For Real Time Tus eq 8.4..8.4
    • Red Hat Enterprise Linux For Real Time Tus eq 8.6..8.6
    • Red Hat Enterprise Linux For Real Time Tus eq 8.8..8.8
    • NetApp E-Series SANtricity OS Controller lte 11.0.0..11.60.3
    Fixed in
    • Linux Kernel 3.16.71
    • Linux Kernel 4.2
    • Linux Kernel 4.4.185
    • Linux Kernel 4.9
    • Linux Kernel 4.9.185
    • Linux Kernel 4.14.133
    • Linux Kernel 4.19.58
    • Linux Kernel 5.1.17

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

    Metrics

    7.8

    Priority

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

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    52.2 %

    EPSS score

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

    Source: FIRST EPSS, percentile 99.0

    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
    217.34 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
    actively exploited
    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
    7.8 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
    7.8
    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
    52.2 %
    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
    99.0
    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
    Actively exploited
    Published
    In CISA KEV since

    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
    CISA assessment (SSVC)
    Exploitation: active · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 4 February 2025

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw gives any low-privileged local user a reliable, interaction-free path to root, and a stable public pkexec-based exploit has circulated for years and ships in common post-exploitation toolkits — hence its very high exploitation likelihood. Attackers use it as a second stage after initial access via a web shell, stolen SSH credentials or a vulnerable application, to gain full control, persistence and access to stored credentials. CISA does not flag ransomware use, but root escalation is a routine precursor to lateral movement. Rate it high for internet-facing and multi-user systems and any remaining legacy estates (Debian 8/9, Ubuntu 16.04); single-purpose appliances without local user accounts can follow the regular patch cycle.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Inventory kernel versions: Query every Linux host for uname -r via config management or EDR. Affected: upstream kernels before 5.1.17 and the 3.16 branch up to 3.16.70 (fixed in 3.16.71). For distribution kernels on Ubuntu 16.04/18.04/19.04, Debian 8/9/10 and Fedora 29: patch available from the vendor — look up the fixed package version in the relevant advisory (USN, DSA/DLA, Fedora update), as backports do not match upstream version numbers.
      • Install the fixed kernel and reboot: The vulnerable kernel keeps running until the host is restarted. Where available, use live patching (Canonical Livepatch, kpatch) as a bridge — confirm coverage of this CVE in the vendor advisory.
      • Prioritise multi-user exposure: Patch first where untrusted or numerous local accounts can run code: jump hosts, shared hosting, CI/CD runners, dev servers, terminal servers and internet-facing web servers (privilege escalation after a web shell).
      • Immediate Yama compensation: Where a reboot is not possible, run sysctl -w kernel.yama.ptrace_scope=2 (only CAP_SYS_PTRACE holders may use ptrace, including via PTRACE_TRACEME) and persist it in /etc/sysctl.d/. Expect debuggers and some monitoring agents to be restricted.
      • Break the public exploit path: The well-known exploit abuses the SUID pkexec binary (Polkit). Where Polkit is not required, strip the SUID bit: chmod 0755 /usr/bin/pkexec — this also closes other pkexec-based escalations.

    2. Runbook step 2

      Mitigation layers

      • Kernel hardening: Roll out kernel.yama.ptrace_scope=2 fleet-wide via Ansible/Puppet; on production servers with no debugging needs evaluate =3 (ptrace fully disabled, only reversible by reboot).
      • Mandatory access control: On SELinux-enforcing RHEL/Fedora hosts, set setsebool -P deny_ptrace on — explicitly named by NVD as a potential workaround. Tighten AppArmor profiles for exposed services (web servers, PHP-FPM) to deny ptrace and execution of /usr/bin/pkexec.
      • SUID reduction: Enumerate SUID binaries (find / -perm -4000 -type f 2>/dev/null) and remove unnecessary ones, especially helpers whose parent drops privileges and calls execve (pkexec and similar Polkit helpers).
      • IAM/least privilege: Minimise interactive shell access on servers, give service accounts /usr/sbin/nologin, enforce SSH via a bastion with MFA. Every local code-execution path you remove lowers exploitability.
      • Containers and workloads: Enforce the default seccomp profile (blocks ptrace in unprivileged containers), never grant CAP_SYS_PTRACE, and disallow privileged containers.
      • Network segmentation: Move unpatchable legacy hosts (notably Debian 8 / kernel 3.16) into dedicated segments; allow inbound SSH only from the admin network.

    3. Runbook step 3

      Detection rules

      • auditd — PTRACE_TRACEME calls: Rule -a always,exit -F arch=b64 -S ptrace -F a0=0x0 -k ptrace_traceme (plus arch=b32). PTRACE_TRACEME from non-debugger processes owned by regular users (auid>=1000) is highly suspicious.
      • Process ancestry (EDR / Sysmon for Linux EID 1): Alert when pkexec is launched by a non-root process and a shell (/bin/sh, /bin/bash) with euid=0 follows, whose auid is a regular user. Sigma shape: parent_image|endswith: /pkexec AND image|endswith: [/sh, /bash] AND user: root.
      • auditd — unexpected UID transition: -a always,exit -F arch=b64 -S execve -F euid=0 -F auid>=1000 -F auid!=4294967295 -k root_exec_by_user, correlated against missing sudo entries in /var/log/auth.log or /var/log/secure. SPL idea: index=linux key=root_exec_by_user | search NOT exe="/usr/bin/sudo".
      • Kernel logs: Panics or oopses referencing ptrace in dmesg/journald — failed attempts can crash the host because of the object-lifetime bug.
      • Artefacts: Freshly compiled ELF files in /tmp, /dev/shm or /var/tmp that subsequently invoke pkexec; raise FIM/EDR alerts on execution from those paths.

    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
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    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
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    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

    In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to create a ptrace relationship, which allows local users to obtain root access by leveraging certain scenarios with a parent-child process relationship, where a parent drops privileges and calls execve (potentially allowing control by an attacker). One contributing factor is an object lifetime issue (which can also cause a panic). Another contributing factor is incorrect marking of a ptrace relationship as privileged, which is exploitable through (for example) Polkit's pkexec helper with PTRACE_TRACEME. NOTE: SELinux deny_ptrace might be a usable workaround in some environments.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog

    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
    netappactive_iq_unified_manager
    • —
    • —
    netappe-series_performance_analyzer
    • —
    • —
    netappe-series_santricity_os_controller
    • 11.0.0 – ≤ 11.60.3
    • —
    netapphci_compute_node
    • —
    • —
    netapphci_management_node
    • —
    • —
    netappservice_processor
    • —
    • —
    netappsolidfire
    • —
    • —
    netappsteelstore_cloud_integrated_storage
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux8.0
    Linuxdebiandebian_linux9.0
    Linuxredhatenterprise_linux7.0
    Linuxredhatenterprise_linux8.0
    Linuxredhatenterprise_linux_for_arm_647.0_aarch64
    Linuxredhatenterprise_linux_for_ibm_z_systems7.0_s390x
    Linuxredhatenterprise_linux_for_real_time8
    Linuxredhatenterprise_linux_for_real_time_for_nfv8.0
    Linuxredhatenterprise_linux_for_real_time_for_nfv_tus8.2
    Linuxredhatenterprise_linux_for_real_time_for_nfv_tus8.4
    Linuxredhatenterprise_linux_for_real_time_for_nfv_tus8.6
    Linuxredhatenterprise_linux_for_real_time_for_nfv_tus8.8
    Linuxredhatenterprise_linux_for_real_time_tus8.2
    Linuxredhatenterprise_linux_for_real_time_tus8.4
    Linuxredhatenterprise_linux_for_real_time_tus8.6
    Linuxredhatenterprise_linux_for_real_time_tus8.8
    Linuxlinuxlinux_kernel—
    Linuxcanonicalubuntu_linux16.04
    Linuxcanonicalubuntu_linux18.04
    Linuxcanonicalubuntu_linux19.04
    Othernetappaff_a700s_firmware—
    Otherfedoraprojectfedora29
    Othernetapph410c_firmware—

    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
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited
    Packet StormLinux PTRACE_TRACEME Broken Permission Object Lifetime Handling (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormSlackware Security Advisory Slackware 14.2 kernel Updates (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormKernel Live Patch Security Notice LSN 0054 1 (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormLinux Polkit pkexec Helper PTRACE_TRACEME Local Root (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormLinux PTRACE_TRACEME Local Root (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—
    Packet StormLinux Kernel 5.1.x PTRACE_TRACEME pkexec Local Privilege Escalation (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • packetstormsecurity.comfiles/153663/Linux-PTRACE_TRACEME-Broken-Permission-Object-Life…x_refsource_MISC, Third-party advisory, Vulnerability database
    • bugs.chromium.orgp/project-zero/issues/detail?id=1903x_refsource_MISC, Exploit, Issue tracking, Patch, Third-party advisory
    • cdn.kernel.orgpub/linux/kernel/v5.x/ChangeLog-5.1.17x_refsource_MISC, Patch, Vendor advisory
    • github.comtorvalds/linux/commit/6994eefb0053799d2e07cd140df6c2ea106c41eex_refsource_MISC, Patch
    • git.kernel.orgcgit/linux/kernel/git/torvalds/linux.git/commit/?id=6994eefb005…x_refsource_MISC, Patch, Vendor advisory
    • bugzilla.suse.comshow_bug.cgi?id=1140671x_refsource_CONFIRM, Issue tracking, Patch, Third-party advisory
    • bugzilla.redhat.comshow_bug.cgi?id=1730895x_refsource_CONFIRM, Issue tracking, Patch
    • lists.fedoraproject.orgFEDORA-2019-a95015e60fVendor advisory, x_refsource_FEDORA, Release notes
    • debian.orgDSA-4484Vendor advisory, x_refsource_DEBIAN, Third-party advisory
    • seclists.org20190722 [SECURITY] [DSA 4484-1] linux security updateMailing list, x_refsource_BUGTRAQ, Issue tracking, Mailing list, Third-party advisory
    • seclists.org20190722 [slackware-security] Slackware 14.2 kernel (SSA:2019-202-01)Mailing list, x_refsource_BUGTRAQ, Issue tracking, Mailing list, Third-party advisory
    • lists.debian.org[debian-lts-announce] 20190723 [SECURITY] [DLA 1862-1] linux security updateMailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • lists.debian.org[debian-lts-announce] 20190723 [SECURITY] [DLA 1863-1] linux-4.9 security updateMailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • packetstormsecurity.comfiles/153702/Slackware-Security-Advisory-Slackware-14.2-kernel-…x_refsource_MISC, Third-party advisory, Vulnerability database
    • security.netapp.comadvisory/ntap-20190806-0001x_refsource_CONFIRM, Third-party advisory
    • access.redhat.comRHSA-2019:2405Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • access.redhat.comRHSA-2019:2411Vendor advisory, x_refsource_REDHAT, Third-party advisory
    • usn.ubuntu.comUSN-4093-1Vendor advisory, x_refsource_UBUNTU, Third-party advisory
    • usn.ubuntu.comUSN-4094-1Vendor advisory, x_refsource_UBUNTU, Third-party advisory
    • usn.ubuntu.comUSN-4095-1Vendor advisory, x_refsource_UBUNTU, Third-party advisory
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