CVE-2026-3548
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 · uneditedTwo buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.
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 confidencewolfSSL contains two buffer overflow vulnerabilities in its CRL parser when handling CRL numbers. A heap-based buffer overflow occurs when improperly storing the CRL number as a hexadecimal string, while a stack-based overflow can happen with sufficiently large CRL numbers. Both vulnerabilities allow out-of-bounds writes when processing crafted CRL files.
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< 5.9.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check wolfSSL versionRun `wolfssl version` or check the library file version. On Linux: `ldd --version` or inspect the library: `strings libwolfssl.so | grep '^5\.'` to find version strings. Check if the version is below 5.9.0.Affected if Installed version is wolfSSL < 5.9.0
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Verify CRL support is compiled inCheck the wolfSSL build configuration. Run `wolfssl cflags` or check compilation flags for `--enable-crl` or `--without-crl`. Also check if the binary links against the CRL-enabled library: `nm libwolfssl.so | grep -i crl` should show CRL-related symbols if enabled.Affected if wolfSSL was compiled with CRL support enabled (--enable-crl)
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Inspect application CRL configurationReview application configuration files, startup scripts, or code that loads CRL files. Check for environment variables or config settings that specify CRL file paths (e.g., `SSL_CERT_FILE`, custom CRL path settings). Look for any .crl files being loaded.Affected if The application loads or processes CRL files from any source
User is affected if wolfSSL version is below 5.9.0 AND CRL support is compiled in AND the application processes CRL files.
Generated from the published advisory. Verify against your own configuration.
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 · scoped5.9.0
Disable CRL support in wolfSSL builds if not required; otherwise ensure CRLs are only loaded from trusted sources and apply vendor patches when available.
wolfSSL 5.9.0 or later
- Identify your current wolfSSL version using `wolfssl version` or checking your build system
- Verify if CRL (Certificate Revocation List) support is enabled in your build - check for `--enable-crl` or `WOLFSSL_CRL` define in your build configuration
- If CRL support is enabled, upgrade to wolfSSL 5.9.0 or later from https://www.wolfssl.com/download/ or your distribution's package manager
- After upgrading, rebuild any applications that link against wolfSSL
- Verify the upgrade was successful by checking `wolfssl version` shows 5.9.0 or later
- If you cannot upgrade immediately and CRL support is not required in production, you may disable CRL parsing via build configuration `--disable-crl` as a temporary mitigation
- Ensure any CRL files loaded from external sources are from trusted/signed sources only
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-3548 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-3548 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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