CriticalCVE-2020-5260

    malicious URLs may cause Git to present stored credentials to the wrong server (CVE-2020-5260)

    Published Sources: CVE.org, OSV

    What is affected, what to do

    Affected versions of Git have a vulnerability whereby Git can be tricked into sending private credentials to a host controlled by an attacker. Git uses external "credential helper" programs to store and retrieve passwords or other credentials from secure storage provided by the operating system.

    An exploit is publicly available. Update Git to version 2.17.4.

    Affected
    • Git gte 2.18.0, < 2.18.3..*
    • Git lt *..2.17.4
    Fixed in
    • Git 2.17.4

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

    Metrics

    9.3

    Priority

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

    Source: Vendor (CNA), CVSS v3

    9.3

    CVSS v3

    Severity Critical on the scale from 0 to 10.

    Source: CVE.org, OSV

    10.0 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 95.6

    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
    119.55 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
    9.3 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
    9.3
    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
    10.0 %
    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
    95.6
    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-20

    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

    Affected versions of Git have a vulnerability whereby Git can be tricked into sending private credentials to a host controlled by an attacker. Git uses external "credential helper" programs to store and retrieve passwords or other credentials from secure storage provided by the operating system. Specially-crafted URLs that contain an encoded newline can inject unintended values into the credential helper protocol stream, causing the credential helper to retrieve the password for one server (e.g., good.example.com) for an HTTP request being made to another server (e.g., evil.example.com), resulting in credentials for the former being sent to the latter. There are no restrictions on the relationship between the two, meaning that an attacker can craft a URL that will present stored credentials for any host to a host of their choosing. The vulnerability can be triggered by feeding a malicious URL to git clone. However, the affected URLs look rather suspicious; the likely vector would be through systems which automatically clone URLs not visible to the user, such as Git submodules, or package systems built around Git. The problem has been patched in the versions published on April 14th, 2020, going back to v2.17.x. Anyone wishing to backport the change further can do so by applying commit 9a6bbee (the full release includes extra checks for git fsck, but that commit is sufficient to protect clients against the vulnerability). The patched versions are: 2.17.4, 2.18.3, 2.19.4, 2.20.3, 2.21.2, 2.22.3, 2.23.2, 2.24.2, 2.25.3, 2.26.1.

    Source: NVD (NIST), OSV (Open Source Vulnerabilities), 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
    gitgit
    • < 2.17.4
    • ≥ 2.18.0, < 2.18.3
    • < 2.17.4
    • 2.22.0 – < 2.22.3
    • 2.17.4
    • —
    • 2.17.4
    • 2.22.3
    git-scmgit
    • 2.19.0 – < 2.19.4
    • 2.23.0 – < 2.23.2
    • 2.21.0 – < 2.21.2
    • 2.18.0 – < 2.18.3
    • 2.20.0 – < 2.20.3
    • 2.25.0 – < 2.25.3
    • 2.24.0 – < 2.24.2
    • 2.26.0 – < 2.26.1
    • 2.19.4
    • 2.23.2
    • 2.21.2
    • 2.18.3
    • 2.20.3
    • 2.25.3
    • 2.24.2
    • 2.26.1
    Distribution and container packages (1)

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

    Distribution and container packages
    Affected versionsFixed in
    bitnamigit
    • 2.22.0
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebiandebian_linux10.0
    Linuxdebiandebian_linux8.0
    Linuxdebiandebian_linux9.0
    Linuxopensuseleap15.1
    Linuxcanonicalubuntu_linux16.04
    Linuxcanonicalubuntu_linux18.04
    Linuxcanonicalubuntu_linux19.10
    Otherfedoraprojectfedora30
    Otherfedoraprojectfedora31
    Otherfedoraprojectfedora32

    Weakness classes (CWE)

    • CWE-20Improper Input Validation

      Class

      The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

      Entry at MITRE CWE-20

    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 StormGit Credential Helper Protocol Newline Injection (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

    • lists.opensuse.orgopenSUSE-SU-2020:0524web, Vendor advisory, x_refsource_SUSE, Third-party advisory
    • lists.opensuse.orgopenSUSE-SU-2020:0598web, Vendor advisory, x_refsource_SUSE, Third-party advisory
    • packetstormsecurity.comfiles/157250/Git-Credential-Helper-Protocol-Newline-Injection.h…web, x_refsource_MISC, Third-party advisory, Vulnerability database
    • openwall.com[oss-security] 20200415 CVE-2020-5260: Git: malicious URLs may cause Git to present stored credentials to the wrong serverweb, Mailing list, x_refsource_MLIST, Mailing list
    • openwall.com[oss-security] 20200415 Re: CVE-2020-5260: Git: malicious URLs may cause Git to present stored credentials to the wrong serverweb, Mailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • openwall.com[oss-security] 20200420 CVE-2020-11008: Git: Malicious URLs can still cause Git to send a stored credential to the wrong serverweb, Mailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • github.comgit/git/commit/9a6bbee8006c24b46a85d29e7b38cfa79e9ab21bweb, x_refsource_MISC, Patch, Third-party advisory
    • github.comgit/git/security/advisories/GHSA-qm7j-c969-7j4qweb, x_refsource_CONFIRM, Mitigation, Patch, Third-party advisory
    • lists.debian.org[debian-lts-announce] 20200415 [SECURITY] [DLA 2177-1] git security updateweb, Mailing list, x_refsource_MLIST, Mailing list, Third-party advisory
    • lists.fedoraproject.orgFEDORA-2020-4e093619bbweb, Vendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2020-c6548b488fweb, Vendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2020-b2a2c830cfweb, Vendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2020-f6b3b6fb18web, Vendor advisory, x_refsource_FEDORA
    • lists.fedoraproject.orgFEDORA-2020-cdef88bb89web, Vendor advisory, x_refsource_FEDORA
    • lore.kernel.orggit/xmqqy2qy7xn8.fsf@gitster.c.googlers.comweb, x_refsource_MISC
    • security.gentoo.orgGLSA-202004-13web, Vendor advisory, x_refsource_GENTOO, Third-party advisory
    • support.apple.comkb/HT211141web, x_refsource_CONFIRM, Third-party advisory
    • usn.ubuntu.comUSN-4329-1web, Vendor advisory, x_refsource_UBUNTU, Third-party advisory
    • debian.orgDSA-4657web, Vendor advisory, x_refsource_DEBIAN, Third-party advisory
    • NVD (NIST)vuln/detail/CVE-2020-5260web
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