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WolfsslApplication

CVE-2020-36177

CRITICAL · 9.8 CVSS v3.1 Published 2021-01-06
Fix available
A fix is available. Upgrade to 4.6.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

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
RsaPad_PSS in wolfcrypt/src/rsa.c in wolfSSL before 4.6.0 has an out-of-bounds write for certain relationships between key size and digest size.

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
How this class of weakness works · CWE-787

The program writes past the bounds of a buffer, overwriting adjacent memory an attacker can turn to their advantage. Crafted input can overwrite control data and redirect execution. Remediation is validating every index and length before a write, plus modern memory-safety mitigations.

General guidance for the out-of-bounds write class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
WolfsslApplication
Affected:< 4.6.0

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
High
Availability
High

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

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 4.6.0 or later
Fixed in 4.6.0
Vendor patch github.com →
Recommended fix High confidence

wolfSSL 4.6.0

  1. 1. Identify current wolfSSL version by checking the version header file or running 'wolfssl -version'
  2. 2. Download wolfSSL 4.6.0 or later from the official wolfSSL repository (https://github.com/wolfSSL/wolfssl/releases)
  3. 3. Review the wolfSSL 4.6.0 release notes for any backward-incompatible changes relevant to your integration
  4. 4. Back up current wolfSSL installation and any custom configurations
  5. 5. Configure the new version: ./configure --prefix=/usr/local (or your preferred installation path)
  6. 6. Compile and install: make && make install
  7. 7. Update library links if necessary: ldconfig (on Linux)
  8. 8. Rebuild and redeploy any applications that link against wolfSSL
Caveat Review 4.6.0 release notes for API/behavior changes; minor version upgrades typically maintain backward compatibility but verify your use case

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,550. Get the upgrade done

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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-2020-36177 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