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Vulnerability Database · Debian · Package report

stunnel4: vulnerability history, versions and safety

stunnel4 is a package in the Debian ecosystem. Vulert records 14 vulnerabilities for it across 7 affected ranges, from May 2003 to Feb 2021. Each vulnerability names the versions it affects, the fixed version to move to, and a workaround where no fix has been published.

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14 vulnerabilities recorded U14
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0 with no fix published

Every vulnerability has a patched version to move to.

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0 in the last 12 months

Nothing new recorded in the last year.

See the disclosure history →
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0 malicious-package vulnerabilities

No published version shipped hostile code.

See all stunnel4 vulnerabilities

Vulert verdict on stunnel4 i

Updated on 23 Oct 2026

Every vulnerability Vulert records for this package has a fix, and the newest was recorded 23 Feb 2021. Apply the fixes listed below and you are clear.

Long-term outlook: usable, with an upgrade 14 vulnerabilities on record across 17 years, none in the last year.

What to do: Move the affected dependencies to the fixed versions listed below, then keep the package monitored so the next vulnerability reaches you. Fix it, then keep watch: Vulert alerts you when a new vulnerability affects the version you run. Monitor it with Vulert →

  • Vulnerabilities on record 14 over 17 years · 0 in the last year i
  • Latest disclosure 23 Feb 2021 i
  • Highest CVSS 7.5 i
  • With no published fix 0 i

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01 Versions

Which versions are affected

Vulert records these vulnerabilities by affected range rather than by individual release, so these are the ranges to check. Filter above to find the version you run.

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Affected range Vulnerabilities
up to 4.04-1 (exclusive) 2
up to 3:5.56+dfsg-8 (exclusive) 2
up to 3:5.18-1 (exclusive) 2
up to 3:4.53-1.1 (exclusive) 2
up to 3:4.42-1 (exclusive) 2
up to 3:4.22-1.1 (exclusive) 2
up to 2:4.04 (exclusive) 2

02 Disclosure history

How often vulnerabilities are recorded

  • 2003 4
  • 2008 2
  • 2011 2
  • 2013 2
  • 2015 2
  • 2021 2

Counted by the year Vulert recorded each vulnerability — the same date the table below shows as disclosed. 0 of the 14 were recorded in the last 12 months.

03 Vulnerabilities

Recorded vulnerabilities for stunnel4

The 5 most severe of 14 vulnerabilities recorded for this package

Search all 14 in the database →
Vulnerability Severity Fixed version ↓ Disclosed ↓
Improper Client Certificate Validation in stunnel4 - CVE-2021-20230 7.5 high 3:5.56+dfsg-8 23 Feb 2021
Critical Remote Code Execution Vulnerability in stunnel4 N/A unrated 3:4.42-1 25 Aug 2011
Privilege Escalation Vulnerability in Stunnel4: Local Hijacking Risk N/A unrated 2:4.04 20 Oct 2003
Certificate Revocation Bypass in stunnel4: CVE-2008-2420 N/A unrated 3:4.22-1.1 23 May 2008
Stunnel4 Vulnerability: Authentication Bypass via Redirect Option N/A unrated 3:5.18-1 14 May 2015

Vulnerability wrong, a fix missing, or a package we should cover? Report it and we will fix the record. Report Vulnerability Provide Feedback

Updated: 23/Oct/2026 · Vulnerabilities in our DB: 524315

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Questions

About stunnel4

Is stunnel4 safe to use?

Vulert records 14 vulnerabilities for stunnel4 in Debian: 0 critical, 0 high, 0 medium and 0 low, plus 14 not yet rated. Every one of them has a published fix, so the practical answer is to run a supported release and keep it patched.

How many vulnerabilities does stunnel4 have?

14 vulnerabilities are recorded for stunnel4 in the Debian ecosystem: 0 critical, 0 high, 0 medium and 0 low, plus 14 not yet rated. The ledger on this page lists the same counts next to the date of the most recent disclosure.

How often are new stunnel4 vulnerabilities disclosed?

0 vulnerabilities were recorded for stunnel4 in the last 12 months, and the oldest entry in this database dates to 12 May 2003. Recency matters more than a lifetime total: it shows how actively new issues are being disclosed for the package you are considering.

Which versions of stunnel4 are affected?

Each vulnerability on this page lists the affected version range and the fixed version to move to. Open the vulnerability for the version you actually run — fixes are specific to a release line, not to the package as a whole.

How do I monitor stunnel4 for upcoming vulnerabilities?

Upload the manifest or SBOM for your application at vulert.com/scanner and Vulert keeps checking the stunnel4 version you actually run against new disclosures, then alerts you when one affects it. There is no installation and no source-code access required.