No exploitation reportedFix available

CVE-2016-9843

Q: Is CVE-2016-9843 actively exploited?

Active exploitation of CVE-2016-9843 has not been confirmed. Its EPSS score was 5.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2016-9843?

CVE-2016-9843 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2017-05-23
Fixed in10.3.11 · 10.2.19 · 10.1.37 · 10.0.37 · 5.5.62

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The crc32_big 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.

Timeline

dates in UTC

2017-05-2304:29CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2016-9843?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2016-9843?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

MariaDB

Branch	Affected	Fixed in	Source
10.3	≥ 10.3.0, < 10.3.11	10.3.11	NVD
10.2	≥ 10.2.0, < 10.2.19	10.2.19	NVD
10.1	≥ 10.1.0, < 10.1.37	10.1.37	NVD
10.0	≥ 10.0.0, < 10.0.37	10.0.37	NVD
5.5	≥ 5.5.0, < 5.5.62	5.5.62	NVD

Node.js

Branch	Affected	Fixed in	Source
7.x	≥ 7.0.0, < 7.6.0	7.6.0	NVD
6.x	≥ 6.9.0, < 6.10.2	6.10.2	NVD
4.x	≥ 4.2.0, < 4.8.2	4.8.2	NVD
4.x	≥ 4.0.0, ≤ 4.1.2	no fix published	NVD
6.x	≥ 6.0.0, ≤ 6.8.1	no fix published	NVD

MySQL

Branch	Affected	Fixed in	Source
5.5	≥ 5.5.0, ≤ 5.5.61	no fix published	NVD
5.6	≥ 5.6.0, ≤ 5.6.41	no fix published	NVD
5.7	≥ 5.7.0, ≤ 5.7.23	no fix published	NVD
8.0	≥ 8.0.0, ≤ 8.0.12	no fix published	NVD

21 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update MariaDB to 10.3.11 · 10.2.19 · 10.1.37 · 10.0.37 · 5.5.62

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
FIRST EPSSEPSS score5.8 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2017-05-23
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2016-9843?

The crc32_big 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.

Is CVE-2016-9843 actively exploited?

Active exploitation of CVE-2016-9843 has not been confirmed. Its EPSS score was 5.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2016-9843?

CVE-2016-9843 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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