dbcve.org
CurlApplication · Haxx

CVE-2017-8816

CRITICAL · 9.8 CVSS v3.1 Published 2017-11-29
Fix available
A fix is available. Upgrade to after 7.56.1 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
The NTLM authentication feature in curl and libcurl before 7.57.0 on 32-bit platforms allows attackers to cause a denial of service (integer overflow and resultant buffer overflow, and application crash) or possibly have unspecified other impact via vectors involving long user and password fields.

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

The NTLM authentication implementation in curl and libcurl versions before 7.57.0 contains an integer overflow vulnerability when processing unusually long username and password fields on 32-bit platforms. This integer overflow leads to a buffer overflow condition that can cause denial of service (application crash) and potentially allow arbitrary code execution or other unspecified impact.

MitigationUpgrade curl and libcurl to version 7.57.0 or later to patch the integer overflow vulnerability in the NTLM authentication code. On 32-bit systems, consider restricting NTLM authentication or implementing input length limits until the upgrade can be applied.

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
CurlApplication
Affected:> 7.36.0, <= 7.56.1
Debian LinuxOperating system
Affected:= 8.0= 9.0
LibcurlApplication
Affected:>= 7.36.0, <= 7.56.1

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:3.1/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. Check curl version
    Run 'curl --version' to see the installed curl version
    Affected if The version shown is greater than 7.36.0 and less than or equal to 7.56.1 (e.g., 7.50.0, 7.56.0, 7.56.1)
  2. Check libcurl version
    Check the libcurl library version by running 'ldd /usr/bin/curl' or checking your application's linked libcurl version
    Affected if The libcurl version is between 7.37.0 and 7.56.1 inclusive
  3. Verify system architecture
    Run 'uname -m' to check if running on 32-bit system (i686, i386, or i586) or check with 'getconf LONG_BIT'
    Affected if The system is 32-bit (output shows i686, i386, or LONG_BIT returns 32)
  4. Check if NTLM authentication is in use
    Search configuration files, scripts, or application code for NTLM authentication usage (look for '--ntlm' flag in curl commands, or NTLM in proxy/authentication settings)
    Affected if NTLM authentication is enabled or configured for curl/libcurl connections

You are affected if you have curl or libcurl version 7.37.0 through 7.56.1 running on a 32-bit system and NTLM authentication is being used

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 a release after 7.56.1
Interim mitigation

Upgrade curl and libcurl to version 7.57.0 or later to patch the integer overflow vulnerability in the NTLM authentication code. On 32-bit systems, consider restricting NTLM authentication or implementing input length limits until the upgrade can be applied.

Recommended fix High confidence

curl/libcurl version 7.57.0 or later

  1. 1. Check current curl/libcurl version by running: curl --version or dpkg -l | grep curl
  2. 2. For Debian systems, update package lists: apt-get update
  3. 3. Upgrade curl/libcurl to version 7.57.0 or later: apt-get install curl libcurl4
  4. 4. Verify the installed version: curl --version or dpkg -l | grep curl
  5. 5. Ensure any applications using libcurl are restarted to load the updated library
Caveat Minimal risk - this is a minor version upgrade within the same major version series; however, test NTLM authentication functionality after upgrade

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

Fix this in Curl Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2017-8816 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2017-8816 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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