CVE Intelligence
High

CVE-2016-9840 — inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified…

inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact by leveraging improper pointer arithmetic.

Published May 23, 2017 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: microfocus

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 4.9% (30-day exploitation probability)+14
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
4.88%
ahead of 92% of scored CVEs · Oct 14, 2026
Affects
Apple
Iphone Os and 19 more
CVSS base
8.8
High · 1 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Apple Iphone Os, Apple Mac Os X, Apple Tvos…).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. EPSS ahead of 92% of scored CVEs: prioritize it in the patch queue.
  6. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Apple Iphone Os < 11 Vulnerable NIST National Vulnerability Database
Apple Mac Os X ≥ 10.0.0 and < 10.13.0 Vulnerable NIST National Vulnerability Database
Apple Tvos < 11.0 Vulnerable NIST National Vulnerability Database
Apple Watchos < 4 Vulnerable NIST National Vulnerability Database
Boost Boost < 1.78.0 Vulnerable NIST National Vulnerability Database
Canonical Ubuntu Linux version 16.04version 18.04 Vulnerable NIST National Vulnerability Database
Debian Debian Linux version 8.0 Vulnerable NIST National Vulnerability Database
Nodejs Node.js ≥ 4.0.0 and ≤ 4.1.2≥ 7.0.0 and < 7.6.0≥ 6.9.0 and < 6.10.2≥ 6.0.0 and ≤ 6.8.1≥ 4.2.0 and < 4.8.2 Vulnerable NIST National Vulnerability Database
Opensuse Leap version 42.1version 42.2 Vulnerable NIST National Vulnerability Database
Opensuse Opensuse version 13.2 Vulnerable NIST National Vulnerability Database
Oracle Database Server version 18c Vulnerable NIST National Vulnerability Database
Oracle Jdk version 1.6.0-update161version 1.7.0-update151version 1.8.0-update144 Vulnerable NIST National Vulnerability Database
Oracle Jre version 1.8.0-update144version 1.7.0-update151version 1.6.0-update161 Vulnerable NIST National Vulnerability Database
Oracle Mysql ≥ 8.0.0 and ≤ 8.0.12≥ 5.7.0 and ≤ 5.7.23≥ 5.6.0 and ≤ 5.6.41≥ 5.5.0 and ≤ 5.5.61 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Desktop version 7.0version 6.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Eus version 7.4version 7.5 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Server version 6.0version 7.0 Vulnerable NIST National Vulnerability Database
Red Hat Enterprise Linux Workstation version 7.0version 6.0 Vulnerable NIST National Vulnerability Database
Red Hat Satellite version 5.8 Vulnerable NIST National Vulnerability Database
Zlib Zlib ≥ 1.2.0.6 and < 1.2.9 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.8 CVSS 3.1 High 2.8 5.9 nvd@nist.gov via NIST National Vulnerability Database
6.8 CVSS 2.0 Medium 8.6 6.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 4.88%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 8.8
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • 2017
  • CVE published
    May 23, 2017 · microfocus

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

31 on the record

Elsewhere on this site

Apple
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-12544 Foreman: ssti and insecure deserialization in foreman-rake configuration 14d
  • CVE-2026-12540 Foreman: command injection in foreman-rake errors:fetch_log via request_id parameter 14d
  • CVE-2026-12541 Foreman: command injection in foreman-rake database tasks 14d
  • CVE-2026-12423 Foreman: unauthenticated information disclosure via provisioning token validation flaw 14d
  • CVE-2026-86950 Apple Multiple Products Out-of-Bounds Write Vulnerability KEV 17d
  • CVE-2026-86903 Out-of-bounds Read in Apple Ipados Sep 14, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2016-9840 is "inftrees.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified…", rated High. It affects Iphone Os (Apple); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.8 describes technical severity. EPSS 4.88% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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