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Debian LinuxOperating system · Debian

CVE-2016-9841

CRITICAL · 9.8 CVSS v3.1 Published 2017-05-23
Fix available
A fix is available. Upgrade to after 8.0.12 or later.
See remediation →
100/100
Remediation priority · Urgent
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
inffast.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic.

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

A detailed technical summary for this CVE is being prepared.

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
Debian LinuxOperating system
Affected:= 8.0
Ubuntu LinuxOperating system
Affected:= 16.04= 18.04
MySQLDatabase / datastore
Affected:>= 5.5.0, <= 5.5.61>= 5.6.0, <= 5.6.41>= 5.7.0, <= 5.7.23>= 8.0.0, <= 8.0.12
SatelliteApplication
Affected:= 5.8
Enterprise Linux DesktopOperating system
Affected:= 6.0= 7.0
Enterprise Linux EusOperating system
Affected:= 7.4= 7.5
Enterprise Linux ServerOperating system
Affected:= 6.0= 7.0
Enterprise Linux WorkstationOperating system
Affected:= 6.0= 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
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 a release after 8.0.12
Vendor patch github.com →
Recommended fix High confidence

zlib 1.2.9 or later; MySQL >= 5.5.62 / >= 5.6.42 / >= 5.7.24 / >= 8.0.13

  1. Identify the zlib library version currently installed on the system (e.g., dpkg -l | grep zlib, rpm -qa | grep zlib, or checking the bundled zlib in MySQL)
  2. For Debian/Ubuntu systems: Run 'apt-get update && apt-get install zlib1g' or 'apt-get upgrade' to obtain the patched zlib package
  3. For RHEL/CentOS systems: Run 'yum update zlib' or 'yum update' to apply the security fix
  4. For MySQL: Upgrade MySQL to a version >= 5.5.62, >= 5.6.42, >= 5.7.24, or >= 8.0.13 which includes the fixed zlib library
  5. Verify the updated zlib version is 1.2.9 or later using 'zlib-flate -version' or checking the library directly
  6. Restart any services that depend on zlib (e.g., web servers, database servers) to load the fixed library
  7. Confirm the vulnerability is resolved by checking the inffast.c code or using vulnerability scanners
Caveat Upgrading MySQL across major versions may require database compatibility checks and potential schema adjustments; some applications may have behavior changes with newer zlib

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

We can identify the exact fixed release, upgrade, and verify it in staging — typical engagement from $2,300. 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-2016-9841 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