CVE-2016-1837

CVE-2016-1837 is a medium-severity vulnerability in Apple Iphone Os with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

• Severity: Medium (CVSS 3.x base score 5.5)
• CVSS v2: 4.3
• EPSS exploit prediction: 4% (90th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-416
• Affected product: Apple Iphone Os
• Published: 2016-05-20
• Last modified: 2026-06-17

Description

Multiple use-after-free vulnerabilities in the (1) htmlPArsePubidLiteral and (2) htmlParseSystemiteral functions 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, allow remote attackers to cause a denial of service via a crafted XML document.

Frequently asked questions

What is CVE-2016-1837?

Multiple use-after-free vulnerabilities in the (1) htmlPArsePubidLiteral and (2) htmlParseSystemiteral functions 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, allow remote attackers to cause a denial of service via a crafted XML document.

How severe is CVE-2016-1837?

CVE-2016-1837 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-1837 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-1837?

CVE-2016-1837 primarily affects Apple Iphone Os. In total, 29 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-1837?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-1837 published?

CVE-2016-1837 was published on 2016-05-20 and last updated on 2026-06-17.

References

• http://lists.apple.com/archives/security-announce/2016/May/msg00001.html
• http://lists.apple.com/archives/security-announce/2016/May/msg00002.html
• http://lists.apple.com/archives/security-announce/2016/May/msg00003.html
• http://lists.apple.com/archives/security-announce/2016/May/msg00004.html
• http://rhn.redhat.com/errata/RHSA-2016-2957.html
• http://www.oracle.com/technetwork/topics/security/bulletinjul2016-3090568.html
• http://www.oracle.com/technetwork/topics/security/linuxbulletinjul2016-3090544.html
• http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
• http://www.securityfocus.com/bid/90691
• http://www.securitytracker.com/id/1035890
• http://www.ubuntu.com/usn/USN-2994-1
• http://xmlsoft.org/news.html
• https://access.redhat.com/errata/RHSA-2016:1292
• https://bugzilla.gnome.org/show_bug.cgi?id=760263
• https://git.gnome.org/browse/libxml2/commit/?id=11ed4a7a90d5ce156a18980a4ad4e53e77384852
• https://kc.mcafee.com/corporate/index?page=content&id=SB10170
• https://support.apple.com/HT206564
• https://support.apple.com/HT206566
• https://support.apple.com/HT206567
• https://support.apple.com/HT206568
• https://www.debian.org/security/2016/dsa-3593
• https://www.tenable.com/security/tns-2016-18

Affected products (29)

• cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
• cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
• cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
• cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
• cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_desktop:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_desktop:7.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server:7.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.2:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.4:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_aus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.2:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.4:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.5:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_eus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_tus:7.2:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_tus:7.3:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_server_tus:7.6:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_workstation:6.0:*:*:*:*:*:*:*
• cpe:2.3:o:redhat:enterprise_linux_workstation:7.0:*:*:*:*:*:*:*
• cpe:2.3:a:mcafee:web_gateway:*:*:*:*:*:*:*:*
• cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

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Other CWE-416 (Use After Free) vulnerabilities

• CVE-2026-13782 — Critical (CVSS 10.0): Use after free in Browser in Google Chrome prior to 150.0.7871.47 allowed a remote attacker who had compromised the…
• CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
• CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
• CVE-2025-24085 — Critical (CVSS 10.0): A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.3 and iPadOS 18.3,…
• CVE-2024-43102 — Critical (CVSS 10.0): Concurrent removals of certain anonymous shared memory mappings by using the UMTX_SHM_DESTROY sub-request of…
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