CVE-2016-9843: Critical severity Apple tvOS vulnerability
Last updated 14 January 2026
Other sources
The crc32big function in crc32.c in zlib 1.2.8 might allow context-dependent attackers to have unspecified impact via vectors involving big-endian CRC calculation.
— Launchpad
There was a small optimization for PowerPCs to pre-increment a pointer when accessing a word, instead of post-incrementing. This required prefacing the loop with a decrement of the pointer, possibly pointing before the object passed. This is not compliant with the C standard, for which decrementing a pointer before its allocated memory is undefined. When tested on a modern PowerPC with a modern compiler, the optimization no longer has any effect.
External References:
https://wiki.mozilla.org/images/0/09/Zlib-report.pdf https://docs.google.com/document/d/10i1KZS5so8xDqH2rplRa2xet0tyTvvJlLbQQmZIUIKE/edit#heading=h.t13tvnx4loq7
Upstream patch:
https://github.com/madler/zlib/commit/d1d577490c15a0c6862473d7576352a9f18ef811
CVE assignment:
http://seclists.org/oss-sec/2016/q4/602
— Red Hat
zlib. Multiple issues were addressed by updating to version 1.2.11.
Credit
Affected Software
Remediation
Patch Available
Patch Available
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2017-13832
- CVE-2017-13829
- CVE-2017-13833
- CVE-2017-7083
- CVE-2017-0381
- CVE-2017-13825
- CVE-2017-13815
- CVE-2017-13828
- CVE-2017-13830
- CVE-2017-13814
- CVE-2017-13831
- CVE-2017-13817
- CVE-2017-13818
- CVE-2017-13836
- CVE-2017-13841
- CVE-2017-13840
- CVE-2017-13842
- CVE-2017-13782
- CVE-2017-13843
- CVE-2017-7114
- CVE-2017-13854
- CVE-2017-13834
- CVE-2017-13873
- CVE-2017-13813
- CVE-2017-13816
- CVE-2017-13812
- CVE-2017-7086
- CVE-2017-1000373
- CVE-2016-9063
- CVE-2017-9233
- CVE-2017-9049
- CVE-2017-5130
- CVE-2017-7376
- CVE-2017-9050
- CVE-2017-13822
- CVE-2017-7080
- CVE-2017-10989
- CVE-2017-7128
- CVE-2017-7129
- CVE-2017-7130
- CVE-2017-7127
- CVE-2017-7081
- CVE-2017-7087
- CVE-2017-7091
- CVE-2017-7092
- CVE-2017-7093
- CVE-2017-7094
- CVE-2017-7095
- CVE-2017-7096
- CVE-2017-7098
- CVE-2017-7099
- CVE-2017-7100
- CVE-2017-7102
- CVE-2017-7104
- CVE-2017-7107
- CVE-2017-7111
- CVE-2017-7117
- CVE-2017-7120
- CVE-2017-7090
- CVE-2017-7109
- CVE-2017-11120
- CVE-2017-11121
- CVE-2017-7103
- CVE-2017-7105
- CVE-2017-7108
- CVE-2017-7110
- CVE-2017-7112
- CVE-2017-7115
- CVE-2017-7116
- CVE-2017-11122
- CVE-2016-9840
- CVE-2016-9841
- CVE-2016-9842
- CVE-2016-9843
- CVE-2016-0736
- CVE-2016-2161
- CVE-2016-5387
- CVE-2016-8740
- CVE-2016-8743
- CVE-2017-13909
- CVE-2017-13809
- CVE-2017-7084
- CVE-2017-7074
- CVE-2017-13820
- CVE-2017-13807
- CVE-2017-7143
- CVE-2017-13821
- CVE-2017-13890
- CVE-2017-13851
- CVE-2017-7138
- CVE-2017-7121
- CVE-2017-7122
- CVE-2017-7123
- CVE-2017-7124
- CVE-2017-7125
- CVE-2017-7126
- CVE-2017-13811
- CVE-2017-13835
- CVE-2017-11103
- CVE-2017-13819
- CVE-2017-13837
- CVE-2017-13906
- CVE-2017-7077
- CVE-2017-7119
- CVE-2017-13810
- CVE-2017-13827
- CVE-2016-4736
- CVE-2018-4302
- CVE-2017-7141
- CVE-2017-7078
- CVE-2017-6451
- CVE-2017-6452
- CVE-2017-6455
- CVE-2017-6458
- CVE-2017-6459
- CVE-2017-6460
- CVE-2017-6462
- CVE-2017-6463
- CVE-2017-6464
- CVE-2016-9042
- CVE-2017-13824
- CVE-2017-13846
- CVE-2017-10140
- CVE-2017-7132
- CVE-2017-13823
- CVE-2017-13808
- CVE-2017-13838
- CVE-2017-7082
- CVE-2017-13908
- CVE-2017-13839
- CVE-2017-13910
- CVE-2017-13863
- CVE-2017-7131
- CVE-2017-7088
- CVE-2017-7072
- CVE-2017-7140
- CVE-2017-7148
- CVE-2017-7097
- CVE-2017-7118
- CVE-2017-7133
- CVE-2017-7075
- CVE-2017-7139
- CVE-2017-13806
- CVE-2017-7085
- CVE-2017-13877
- CVE-2017-7146
- CVE-2017-6211
- CVE-2017-7145
- CVE-2017-7089
- CVE-2017-7106
- CVE-2017-7144
- CVE-2017-7142
Frequently Asked Questions
What is CVE-2016-9843?
CVE-2016-9843 is a vulnerability in zlib 1.2.8 that can allow context-dependent attackers to have unspecified impact via vectors involving big-endian CRC calculation.
What is the severity of CVE-2016-9843?
The severity of CVE-2016-9843 is critical with a CVSS score of 9.8.
How can I fix CVE-2016-9843?
CVE-2016-9843 can be fixed by updating zlib to version 1.2.9 or later.
Where can I find more information about CVE-2016-9843?
You can find more information about CVE-2016-9843 at the following references: [link1], [link2], [link3].