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Vulnerability Database · Debian · Package report

zlib: vulnerability history, versions and safety

zlib is a package in the Debian ecosystem. Vulert records 7 vulnerabilities for it across 17 releases, from Mar 2003 to Feb 2026. 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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7 vulnerabilities recorded U7
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1 with no fix published

No patched version yet — these are the ones to plan around.

See the unfixed vulnerabilities →
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2 in the last 12 months

Most recent disclosure 18 Feb 2026.

See the disclosure history →
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0 malicious-package vulnerabilities

No published version shipped hostile code.

See all zlib vulnerabilities

Vulert verdict on zlib i

Updated on 23 Oct 2026

Careful: one of the 7 vulnerabilities Vulert records for this package has no fix yet. Plan around that one, or apply its workaround. The rest have a fixed version to move to.

Long-term outlook: usable, but needs attention 7 vulnerabilities on record across 22 years, 2 in the last year.

What to do: Plan around the 1 vulnerability with no published fix: each lists the affected range and any workaround that reduces exposure. No fix yet: Vulert alerts you the moment one is published. Monitor it with Vulert →

  • Vulnerabilities on record 7 over 22 years · 2 in the last year i
  • Latest disclosure 18 Feb 2026 i
  • Highest CVSS 2.9 i
  • With no published fix 1 i

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01 Versions

Which versions are affected

Every version Vulert holds for zlib, newest first, with the vulnerabilities that name it. A version with a count of zero has no recorded vulnerabilities; open a version to see the vulnerabilities it is exposed to.

Newest 17 of 17 versions on record. Severity counts are the vulnerabilities recorded against that exact release.

02 Disclosure history

How often vulnerabilities are recorded

  • 2003 2
  • 2004 2
  • 2022 1
  • 2026 2

Counted by the year Vulert recorded each vulnerability — the same date the table below shows as disclosed. 2 of the 7 were recorded in the last 12 months.

03 Vulnerabilities

Recorded vulnerabilities for zlib

The 5 most severe of 7 vulnerabilities recorded for this package

Search all 7 in the database →
Vulnerability Severity Fixed version ↓ Disclosed ↓
CPU Consumption Vulnerability in zlib Package: CVE-2026-27171 2.9 low No fix published 18 Feb 2026
Heap-based Buffer Overflow in zlib N/A unrated 1:1.2.11.dfsg-2+deb11u2 25 Aug 2022
Buffer Overflow Vulnerability in zlib Package: CVE-2003-0107 N/A unrated 1:1.1.4-10 07 Mar 2003
Denial of Service Vulnerability in ZLib Compression Library N/A unrated 1:1.2.1.1-6 20 Oct 2004
Buffer Overflow Vulnerability in zlib Package: CVE-2003-0107 N/A unrated 1:1.1.4-10 07 Mar 2003

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

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Questions

About zlib

Is zlib safe to use?

Vulert records 7 vulnerabilities for zlib in Debian: 0 critical, 0 high, 0 medium and 0 low, plus 7 not yet rated. 1 of them has no published fix yet, so that is the one to avoid or mitigate.

How many vulnerabilities does zlib have?

7 vulnerabilities are recorded for zlib in the Debian ecosystem: 0 critical, 0 high, 0 medium and 0 low, plus 7 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 zlib vulnerabilities disclosed?

2 vulnerabilities were recorded for zlib in the last 12 months, and the oldest entry in this database dates to 07 Mar 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 zlib 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 zlib for upcoming vulnerabilities?

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