SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2016-1839

The xmlDictAddString function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted…

EXPLOIT ✓MEDIUM 5.5EPSS 7.35%

Does this matter?

A public exploit is published in Exploit-DB (verified), so the technical barrier is gone even though the severity is medium and EPSS is 7.3%. Treat it as high on anything reachable from the internet.

Description

The xmlDictAddString function in libxml2 before 2.9.4, as used in Apple iOS before 9.3.2, OS X before 10.11.5, tvOS before 9.2.1, and watchOS before 2.2.1, allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted XML document.

CVSS 3.0
5.5 MEDIUMCVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS
7.35% probability · 94th percentile
Public exploits
1 in Exploit-DB · verified · first 24 February 2016
CISA KEV
Not listed
Weakness
CWE-125
Affected
apple/iphone os · apple/mac os x · apple/tvos · apple/watchos · canonical/ubuntu linux · debian/debian linux · redhat/enterprise linux desktop · redhat/enterprise linux server · redhat/enterprise linux server aus · redhat/enterprise linux server eus · redhat/enterprise linux server tus · redhat/enterprise linux workstation · mcafee/web gateway · xmlsoft/libxml2
Source
product-security@apple.com
EPSS trend
0%8%15%21 September 2026: 12.83%22 September 2026: 7.35%26 October 2026: 7.35%21 September 202626 October 2026

EPSS moved from 12.8% on 21 September 2026 to 7.3% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

Public exploits (1)

Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.

EDB-IDTitleTypePublishedVerified
EDB-39491source ↗libxml2 - xmlDictAddString Heap Buffer Overreadlinux · Google Security Researchdos24 February 2016yes

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.