HighCVE-2026-82049

    tarfile extraction filters allow file modification and content disclosure via hard link to symlink (CVE-2026-82049)

    Published Last modified Sources: SUSE, Red Hat, BSI, OSV, CVE.org, Msrc Update Guide

    What is affected, what to do

    In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.

    Update Python Software Foundation CPython to version 3.10.22, Python Software Foundation CPython to version 3.11.17, Python Software Foundation CPython to version 3.12.15.

    Affected
    • Python Software Foundation CPython lt *..3.10.22
    • Python Software Foundation CPython lt 3.11.0..3.11.17
    • Python Software Foundation CPython lt 3.12.0..3.12.15
    • Python Software Foundation CPython lt 3.13.0..3.13.16
    • Python Software Foundation CPython lt 3.14.0a1..3.14.0b1
    Fixed in
    • Python Software Foundation CPython 3.10.22
    • Python Software Foundation CPython 3.11.17
    • Python Software Foundation CPython 3.12.15
    • Python Software Foundation CPython 3.13.16
    • Python Software Foundation CPython 3.14.0b1

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

    Metrics

    8.4

    Priority

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

    Source: Vendor (CNA), CVSS v4

    8.4

    CVSS v4

    Severity High on the scale from 0 to 10.

    Source: SUSE, Red Hat, BSI, OSV, CVE.org, Msrc Update Guide

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 8.3

    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
    69.93 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
    8.4 Methodology
    CVSS v4

    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
    8.4
    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
    0.2 %
    Low — model estimates < 1% 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
    8.3
    Low — this CVE sits in the lower 10% of all CVEs scored today.
    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-59

    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

    In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.

    Source: suse_csaf, redhat_csaf, BSI WID Portal, BSI CSAF, OSV (Open Source Vulnerabilities), NVD (NIST), cvelistv5, Microsoft Security Update Guide

    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
    Python Software FoundationCPython
    • 3.13.0 – < 3.13.16
    • 3.12.0 – < 3.12.15
    • 3.11.0 – < 3.11.17
    • < 3.10.22
    • 3.14.0a1 – < 3.14.0b1
    • 3.13.16
    • 3.12.15
    • 3.11.17
    • 3.10.22
    • 3.14.0b1
    Open SourcePython CPython
    • < 3.14.0b1
    • 3.14.0b1
    Distribution and container packages (3)

    Downstream packages (e.g. Bitnami, Debian, Ubuntu, Red Hat). Versions refer to the distribution, not the vendor.

    Distribution and container packages
    Affected versionsFixed in
    bitnamipython-min
    • 3.13.0
    • 3.12.0
    • 3.11.0
    • —
    • —
    • —

    Vendors and products

    Weakness classes (CWE)

    • CWE-59Improper Link Resolution Before File Access ('Link Following')

      Base

      The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

      Entry at MITRE CWE-59

    References & sources

    • github.compython/cpython/commit/5a57248b22ad3b9aafcaaadae2c304a1923daecafix, Patch
    • github.compython/cpython/issues/157190report, Issue tracking
    • github.compython/cpython/pull/157191web, Patch
    • mail.python.orgarchives/list/security-announce@python.org/thread/EFJWGAZJA56AK…advisory, Vendor advisory
    • github.compython/cpython/commit/b38be2e6cf9d989075ab73412c63e003ebad4ff3fix, Patch
    • github.compython/cpython/commit/b8f23e307097552eaea2604383a12ab280520d0dfix, Patch
    • openwall.comlists/oss-security/2026/09/14/27
    • NVD (NIST)vuln/detail/CVE-2026-82049web
    • github.compython/cpython/commit/197663d63afed27f66e10e23c194e8a634e60913Patch
    • github.compython/cpython/commit/28f315486b3da0352b9a1de1c3c97f4127ba4771Patch
    • github.compython/cpython/commit/c66df4e70435d257fd488b35ea129c6f317433a8Patch
    • github.compython/cpython/commit/cc1689830c6b9aaddded2fb9f2fe8116867e2c0ePatch
    • github.compython/cpython/commit/cccc7ec30212dba2abef53ce4a2bed112ddb690cfix, Patch

    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 modifiedpython.org

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/python/cpython/commit/cccc7ec30212dba2abef53ce4a2bed112ddb690c

      Source identifier: cna@python.org

    2. Record modifiedpython.org

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82049.json">CVE-2026-82049</a>

      Source identifier: cna@python.org

    3. Record modifiedpython.org

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82049.json">CVE-2026-82049</a>

      Source identifier: cna@python.org

    4. Record modifiedpython.org

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/python/cpython/commit/c66df4e70435d257fd488b35ea129c6f317433a8
      Referenceadded
      —
      https://github.com/python/cpython/commit/cc1689830c6b9aaddded2fb9f2fe8116867e2c0e

      Source identifier: cna@python.org

    5. Record modifiedpython.org

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://github.com/python/cpython/commit/197663d63afed27f66e10e23c194e8a634e60913
      Referenceadded
      —
      https://github.com/python/cpython/commit/28f315486b3da0352b9a1de1c3c97f4127ba4771

      Source identifier: cna@python.org

    Show 6 older changes

    1. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentchanged
      {"id":"CVE-2026-82049","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-14T19:42:40.262634Z"}
      {"id":"CVE-2026-82049","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-15T00:00:00+00:00"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedpython.org

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82049.json">CVE-2026-82049</a>
      Referenceadded
      —
      https://github.com/python/cpython/commit/b38be2e6cf9d989075ab73412c63e003ebad4ff3
      Referenceadded
      —
      https://github.com/python/cpython/commit/b8f23e307097552eaea2604383a12ab280520d0d

      Source identifier: cna@python.org

    3. Record modifiedpython.org

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82049.json">CVE-2026-82049</a>

      Source identifier: cna@python.org

    4. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-82049","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-14T19:42:40.262634Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    5. Record modifiedCVE Program

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      http://www.openwall.com/lists/oss-security/2026/09/14/27

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

    6. Receivedpython.org

      CVSS V4.0: AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

      Weakness type: CWE-59

      Description added or changed

      Show 8 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.
      CVSSadded
      —
      AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      Weakness type (CWE)added
      —
      CWE-59
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/82xxx/CVE-2026-82049.json">CVE-2026-82049</a>
      Referenceadded
      —
      https://github.com/python/cpython/commit/5a57248b22ad3b9aafcaaadae2c304a1923daeca
      Referenceadded
      —
      https://github.com/python/cpython/issues/157190
      Referenceadded
      —
      https://github.com/python/cpython/pull/157191
      Referenceadded
      —
      https://mail.python.org/archives/list/security-announce@python.org/thread/EFJWGAZJA56AKSBR2WHMHQZO7RRLZPRH/

      Source identifier: cna@python.org

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