HighCVE-2026-78254

    Apache Ant: Path traversal in ftp and scp tasks allows arbitrary file write (CVE-2026-78254)

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

    What is affected, what to do

    The ftp and scp tasks of Apache Ant can download files from a remote server. A malicious server can provide relative paths that allow it to write outside of the dedicated target directory for the download, making it possible to overwrite files of the attacker's choice using the permissions of the user running Ant in versions prior to Ant 1.10.18.

    Update Apache Ant to version 1.10.18.

    Affected
    • Apache Ant lt 1.2..1.10.18
    Fixed in
    • Apache Ant 1.10.18

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

    Metrics

    7.4

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.4

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SUSE, BSI, CVE.org, Msrc Update Guide

    0.5 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 43.0

    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
    78.99 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
    7.4 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
    7.4
    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
    0.5 %
    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
    43.0
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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-23

    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 ftp and scp tasks of Apache Ant can download files from a remote server. A malicious server can provide relative paths that allow it to write outside of the dedicated target directory for the download, making it possible to overwrite files of the attacker's choice using the permissions of the user running Ant in versions prior to Ant 1.10.18. In order to exploit this vulnerability, the server would either have to be malicious or be subject to a machine-in-the-middle attack. Additionally in the case of scp or the ftp task using ftps the server must pass the server identity checks performed by the tasks. For ftp tasks not using ftps a malicious server could act as a machine-in-the-middle to provide malicious files. Starting with Ant 1.10.18 both tasks will prevent writing outside of the destination directory by default. An option is available to disable this behavior in the unlikely case that the old behavior is required by existing build files. Mitigations: Users of scp and ftp (when using ftps) in any version of Ant should not bypass server identity checks. Users of ftp not using ftps should switch to ftps where possible. All users are recommended to upgrade to Apache Ant 1.10.18, which fixes this issue.

    Source: suse_csaf, BSI CSAF, BSI WID Portal, cvelistv5, Microsoft Security Update Guide, NVD (NIST), CVE.org (MITRE)

    Affected products

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

    Affected products
    VendorProductAffected versionsFixed in
    Apache Software FoundationApache Ant
    • 1.2 – < 1.10.18
    • 1.10.18
    apacheant
    • < 1.10.18
    • 1.10.18
    ApacheAnt
    • < 1.10.18
    • 1.10.18
    OracleConstruction and Engineering
    • 22.12.0-22.12.15
    • 24.12.0-24.12.16
    • 25.12.0-25.12.9
    • 21.12.0-21.12.18
    • 23.12.0-23.12.16
    • 22.12.0.0-22.12.21.4
    • 23.12.0-23.12.20
    • 21.12.0.0-21.12.21.9
    • 21.12.0-21.12.17
    • 25.12.0-25.12.8
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —

    Weakness classes (CWE)

    • CWE-23Relative Path Traversal

      Base

      The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize sequences such as ".." that can resolve to a location that is outside of that directory.

      Entry at MITRE CWE-23

    References & sources

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. Initial Analysisnvd@nist.gov

      • CPE Configuration: after OR *cpe:2.3:a:apache:ant:*:*:*:*:*:*:*:* versions up to (excluding) 1.10.18
      • Reference Type: after Apache Software Foundation: https://lists.apache.org/thread/05s46qrlbhd06c6rsgvxh8zo0l4p9scz Types: Mailing List, Vendor Advisory
      • Reference Type: after CVE: http://www.openwall.com/lists/oss-security/2026/09/06/2 Types: Mailing List, Third Party Advisory

    2. CVE Modified134c704f-9b21-4f2e-91b3-4a467353bcc0

      • CVSS V3.1: after AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
      • SSVC: after {"id":"CVE-2026-78254","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalI…

    3. CVE Modifiedaf854a3a-2127-422b-91ae-364da2661108

      • Reference: after http://www.openwall.com/lists/oss-security/2026/09/06/2

    4. New CVE Receivedsecurity@apache.org

      • Description: after The ftp and scp tasks of Apache Ant can download files from a remote server. A malicious server can provide relative paths that allow it to write outside of the dedicated target directory for the download, making it possible to overwrite files of the attacker's choice using the permissions of the user running Ant in versions prior to Ant 1.10.18. In order to exploit this vulnerability, the server would either have to be malicious or be subject to a machine-in-the-middle attack. Additionally in the case of scp or the ftp task using ftps the server must pass the server identity checks performed by the tasks. For ftp tasks not using ftps a malicious server could act as a machine-in-the-middle to provide malicious files. Starting with Ant 1.10.18 both tasks will prevent writing outside of the destination directory by default. An option is available to disable this behavior in the unlikely case that the old behavior is required by existing build files. Mitigations: Users of scp and ftp (when using ftps) in any version of Ant should not bypass server identity checks. Users of ftp not using ftps should switch to ftps where possible. All users are recommended to upgrade to Apache Ant 1.10.18, which fixes this issue.
      • CWE: after CWE-23
      • Affected: after New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/78xxx/CVE-2026-78254.json">CVE-2026-78254</a>
      • Reference: after https://lists.apache.org/thread/05s46qrlbhd06c6rsgvxh8zo0l4p9scz
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