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CVE-2020-12762

21
FAUCET Score

CVE-2020-12762 is an integer overflow and out-of-bounds write vulnerability in json-c versions up to 0.14, affecting products from vendors like Canonical, Debian, Fedora, and Siemens. With a CVSS score of 7.8 (HIGH), it allows an unauthenticated attacker to achieve high impact on confidentiality, integrity, and availability through local access and user interaction, typically via a crafted large JSON file. Despite its severity, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.15-20200726CPE matchmatch criteria
cpe:2.3:a:json-c:json-c:*:*:*:*:*:*:*:*
30CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
31CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
32CPE matchmatch criteria
cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.8HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.89%
Probability of exploitation in next 30 days
EPSS Percentile
77.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0189 is in the 76th percentile among its peer group of 11,617 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (18)

github_advisorypatch availablevia nvd_reference
View patch
microsoftpatch availablevia msrc
Product: 19177-16820Fixed in: 0.14-2
microsoftpatch availablevia msrc
Product: 19178-16823Fixed in: 0.15-2
microsoftpatch availablevia msrc
Product: cbl2 json-c 0.15-2 on CBL Mariner 2.0Fixed in: 0.15-2
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 0.14-2
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 0.14-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 0.14-3
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 0.14-3
microsoftpatch availablevia msrc
Product: cm1 json-c 0.14-2 on CBL Mariner 1.0Fixed in: 0.14-2
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.0 Extended Update SupportFixed in: libfastjson-0:0.99.9-3.el9_0.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: libfastjson-0:0.99.9-5.el9
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.2 Extended Update SupportFixed in: libfastjson-0:0.99.9-3.el9_2.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: json-c-0:0.13.1-2.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: libfastjson-0:0.99.9-2.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.6 Extended Update SupportFixed in: libfastjson-0:0.99.9-1.el8_6.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.8 Extended Update SupportFixed in: libfastjson-0:0.99.9-1.el8_8.1
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: json-c
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: json-c

Vendor Advisories (3)

microsoft2020-Aug/CVE-2020-12762

CVE-2020-12762

Aug 11, 2020
microsoft2020-May/CVE-2020-12762Important

json-c through 0.14 has an integer overflow and out-of-bounds write via a large JSON file as demonstrated by printbuf_memappend.

May 12, 2020
redhatCVE-2020-12762Moderate

libfastjson: integer overflow and out-of-bounds write via a large JSON file

May 2, 2020

References

lists.debian.org / debian-lts-announce/2025/07/msg00021.html
cert-portal.siemens.com / productcert/pdf/ssa-637483.pdf
Third Party Advisory
github.com / json-c/json-c/pull/592
ExploitPatchThird Party Advisory
github.com / rsyslog/libfastjson/issues/161
ExploitThird Party Advisory
lists.debian.org / debian-lts-announce/2020/05/msg00032.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2020/05/msg00034.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2020/07/msg00031.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2023/06/msg00023.html
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CBR36IXYBHITAZFB5PFBJTED22WO5ONB
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/CQQRRGBQCAWNCCJ2HN3W5SSCZ4QGMXQI
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/W226TSCJBEOXDUFVKNWNH7ETG7AR6MCS
security.gentoo.org / glsa/202006-13
Third Party Advisory
security.netapp.com / advisory/ntap-20210521-0001
Third Party Advisory
usn.ubuntu.com / 4360-1
Third Party Advisory
usn.ubuntu.com / 4360-4
Third Party Advisory
debian.org / security/2020/dsa-4741
Third Party Advisory