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PicotcpApplication · Altran

CVE-2020-17441

CRITICAL · 9.1 CVSS v3.1 Published 2020-12-11
Fix available
A fix is available. Upgrade to 3.7.0 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
An issue was discovered in picoTCP 1.7.0. The code for processing the IPv6 headers does not validate whether the IPv6 payload length field is equal to the actual size of the payload, which leads to an Out-of-Bounds read during the ICMPv6 checksum calculation, resulting in either Denial-of-Service or Information Disclosure. This affects pico_ipv6_extension_headers and pico_checksum_adder (in pico_ipv6.c and pico_frame.c).

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

picoTCP 1.7.0 fails to validate the IPv6 payload length field against the actual payload size during IPv6 header processing. This missing bounds check in pico_ipv6_extension_headers and pico_checksum_adder functions causes an out-of-bounds read when calculating ICMPv6 checksums, potentially allowing remote attackers to trigger DoS or read sensitive memory contents.

MitigationAdd validation in pico_ipv6.c and pico_frame.c to verify that the IPv6 payload length field matches the actual payload size before performing ICMPv6 checksum calculations; reject packets with mismatched lengths.

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
PicotcpApplication
Affected:<= 1.7.0
Mplab HarmonyApplication
Affected:>= 3.0.0, < 3.7.0

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
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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. Identify the picoTCP or MPLAB Harmony version in use
    Check your project files, build system, or library manifests for the version string; common locations include version.h, a README, or dependency management files. For MPLAB Harmony, check the harmony version file or the version field in the MHC configuration.
    Affected if The version is 1.7.0 or lower for Altran Picotcp, or between 3.0.0 and below 3.7.0 for Microchip MPLAB Harmony.
  2. Confirm IPv6 support is enabled
    Inspect your build configuration or #define statements for IPv6 enablement flags. Look for options like PICO_SUPPORT_IPV6, PICO_IPV6, or similar configuration macros in your project header files or build scripts.
    Affected if IPv6 support is compiled/enabled in the firmware or application.
  3. Confirm ICMPv6 processing is enabled
    Inspect your configuration for ICMPv6-related build flags such as PICO_SUPPORT_ICMP6, PICO_ICMP6, or checks for icmpv6 module inclusion in the build.
    Affected if ICMPv6 is enabled, as the vulnerability triggers during ICMPv6 checksum calculation.
  4. Inspect pico_ipv6.c for payload length validation
    Locate the pico_ipv6.c source file in your codebase and search for the pico_ipv6_extension_headers function. Verify whether there is bounds-checking code that compares the IPv6 payload length field against the actual packet payload size before processing.
    Affected if The function contains no validation comparing the IPv6 payload length header field to the actual received payload size, or the check is missing entirely.
  5. Inspect pico_frame.c for checksumadder validation
    Locate the pico_frame.c source file and find the pico_checksum_adder function. Check whether there is validation to ensure the payload length matches the actual data buffer before performing the checksum calculation.
    Affected if The function performs checksum calculations on IPv6 packets without first validating that the payload length field matches the available payload data.

You are affected if your picoTCP version is 1.7.0 or lower (or MPLAB Harmony is 3.0.0 to below 3.7.0), IPv6 and ICMPv6 are enabled, and the source code lacks payload length validation in pico_ipv6_extension_headers or pico_checksum_adder functions.

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.

From vendor data
Upgrade available Upgrade to 3.7.0 or later
Fixed in 3.7.0
Interim mitigation

Add validation in pico_ipv6.c and pico_frame.c to verify that the IPv6 payload length field matches the actual payload size before performing ICMPv6 checksum calculations; reject packets with mismatched lengths.

Fix this in Picotcp Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2020-17441 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