dbcve.org
CurlApplication · Haxx

CVE-2022-42916

HIGH · 7.5 CVSS v3.1 Published 2022-10-29
Fix available
A fix is available. Upgrade to 7.86.0 / 8.2.12 or later.
See remediation →
84/100
Remediation priority · High
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
In curl before 7.86.0, the HSTS check could be bypassed to trick it into staying with HTTP. Using its HSTS support, curl can be instructed to use HTTPS directly (instead of using an insecure cleartext HTTP step) even when HTTP is provided in the URL. This mechanism could be bypassed if the host name in the given URL uses IDN characters that get replaced with ASCII counterparts as part of the IDN conversion, e.g., using the character UTF-8 U+3002 (IDEOGRAPHIC FULL STOP) instead of the common ASCII full stop of U+002E (.). The earliest affected version is 7.77.0 2021-05-26.

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

In curl before 7.86.0, the HSTS (HTTP Strict Transport Security) check can be bypassed by using IDN (Internationalized Domain Name) characters in the URL hostname that get replaced with ASCII counterparts during IDN conversion. For example, using the IDEOGRAPHIC FULL STOP (U+3002) instead of the standard ASCII full stop (U+002E) allows curl to remain on HTTP instead of upgrading to HTTPS as HSTS would normally enforce.

MitigationUpgrade curl to version 7.86.0 or later to obtain the patch that properly validates IDN characters during HSTS processing.

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:>= 7.77.0, < 7.86.0
FedoraOperating system
Affected:= 35= 36= 37
macOSOperating system
Affected:< 12.6.3>= 13.0, < 13.2
Universal ForwarderApplication
Affected:>= 8.2.0, < 8.2.12>= 9.0.0, < 9.0.6= 9.1.0

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
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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` and look at the version number in the first line (e.g., curl 7.84.0)
    Affected if The version is 7.77.0 or higher but lower than 7.86.0
  2. Check if HSTS support is compiled in
    Run `curl --version` and examine the features list. Look for "HSTS" in the output.
    Affected if HSTS appears in the features list, meaning HSTS support is enabled in this curl build
  3. Check for HSTS cache file
    Inspect the default HSTS cache location. Common paths: `~/.curl/hsts` or check CURL_ENV_PTR for custom paths. Use `find ~ -name "hsts*" 2>/dev/null` to search.
    Affected if An HSTS cache file exists and is being used by curl

You are affected if curl version is 7.77.0 or higher but below 7.86.0 AND HSTS support is compiled into your curl binary.

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 7.86.0 / 8.2.12 / 9.0.6 or later
Fixed in 7.86.08.2.129.0.6
Interim mitigation

Upgrade curl to version 7.86.0 or later to obtain the patch that properly validates IDN characters during HSTS processing.

Recommended fix High confidence

curl 7.86.0 or later

  1. Check current curl version by running: curl --version
  2. Upgrade curl to version 7.86.0 or later (e.g., curl 7.86.0, 7.87.0, or latest stable)
  3. For Fedora systems: dnf update curl to receive the patched version
  4. For macOS: Update via Homebrew (brew upgrade curl) or install from curl.se/download.html
  5. For Splunk Universal Forwarder: Upgrade the Splunk product which bundles the fixed curl library
  6. Verify the fix by running: curl --version and confirming the version is >= 7.86.0
  7. Test that IDN domains with non-ASCII characters (like U+3002) now correctly upgrade to HTTPS via HSTS
Caveat Minimal risk - this is a security fix; IDN behavior changes are the intended fix, not a breaking change

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

Fix this in Curl Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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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-2022-42916 in production — separate from our analysis above.

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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