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Ubuntu LinuxOperating system · Canonical

CVE-2018-14618

CRITICAL · 9.8 CVSS v3.0 Published 2018-09-05
Fix available
A fix is available. Upgrade to 7.61.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
curl before version 7.61.1 is vulnerable to a buffer overrun in the NTLM authentication code. The internal function Curl_ntlm_core_mk_nt_hash multiplies the length of the password by two (SUM) to figure out how large temporary storage area to allocate from the heap. The length value is then subsequently used to iterate over the password and generate output into the allocated storage buffer. On systems with a 32 bit size_t, the math to calculate SUM triggers an integer overflow when the password length exceeds 2GB (2^31 bytes). This integer overflow usually causes a very small buffer to actually get allocated instead of the intended very huge one, making the use of that buffer end up in a heap buffer overflow. (This bug is almost identical to CVE-2017-8816.)

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

curl before 7.61.1 contains a heap buffer overflow in NTLM authentication. The function Curl_ntlm_core_mk_nt_hash calculates buffer size by multiplying password length by 2, but on 32-bit systems when the password exceeds 2GB, an integer overflow causes a small buffer to be allocated, leading to heap overflow during password processing.

MitigationUpgrade curl to version 7.61.1 or later to patch the integer overflow in NTLM authentication. On 32-bit systems, prioritize upgrading given the direct exploitability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Ubuntu LinuxOperating system
Affected:= 12.04= 14.04= 16.04= 18.04
Debian LinuxOperating system
Affected:= 9.0
Enterprise LinuxOperating system
Affected:= 6.0= 7.0= 7.4= 7.5= 7.6
LibcurlApplication
Affected:< 7.61.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed curl version
    Run 'curl --version' or check package manager: 'dpkg -l | grep curl' (Debian/Ubuntu) or 'rpm -q curl' (RHEL)
    Affected if Version is lower than 7.61.1, or version cannot be determined and your distribution is in the affected list (Ubuntu 12.04-18.04, Debian 9.0, RHEL 6.0-7.6)
  2. Identify if curl library is used by applications
    Check for libcurl presence: 'ldd <application> | grep curl' or 'dpkg -l | grep libcurl' / 'rpm -qa | grep libcurl'
    Affected if libcurl version is installed and is lower than 7.61.1
  3. Confirm system architecture
    Run 'uname -m' or 'getconf LONG_BIT' - look for i386, i686, or 32-bit indicator
    Affected if Running a 32-bit operating system (the overflow only triggers on 32-bit systems with passwords exceeding 2GB)
  4. Detect if NTLM authentication is configured or in use
    Review application configs for NTLM, NTLM-v2, or --ntlm curl options; check environment variables like 'NTLM_AUTH' or proxy configurations using NTLM
    Affected if Applications or scripts use NTLM authentication with curl, as this is the vulnerable code path

You are affected if curl or libcurl version is below 7.61.1 AND NTLM authentication is used AND you are on a 32-bit system with potential for large password handling; otherwise the overflow requires password lengths exceeding 2GB which is rare but possible in specific configurations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.61.1 or later
Fixed in 7.61.1
Interim mitigation

Upgrade curl to version 7.61.1 or later to patch the integer overflow in NTLM authentication. On 32-bit systems, prioritize upgrading given the direct exploitability.

Recommended fix High confidence

curl version 7.61.1 or later (libcurl)

  1. Identify the current curl version by running: curl --version or dpkg -l | grep curl (Debian/Ubuntu) or rpm -qa | grep curl (RHEL/CentOS)
  2. Stop any services or applications that are using curl to ensure a safe upgrade
  3. Update the curl package using your distribution's package manager: For Ubuntu/Debian: sudo apt-get update && sudo apt-get install curl libcurl3 (or libcurl4 for newer systems), For RHEL/CentOS 6/7: sudo yum update curl
  4. Alternatively, download and install curl 7.61.1 or later directly from curl.haxx.se or compile from source: wget https://curl.haxx.se/download/curl-7.61.1.tar.gz && tar -xzf curl-7.61.1.tar.gz && cd curl-7.61.1 && ./configure && make && sudo make install
  5. Verify the installed version: curl --version and confirm it shows version 7.61.1 or higher
  6. Restart any affected services that rely on curl
Caveat Major version upgrades of curl may introduce minor API/ABI changes; test in staging environment before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Ubuntu Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-14618 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data