CVE-2020-12762

Exp

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

Published: 2020-05-09 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-12762 is rated High Exploit Risk (74.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.89%). 2 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.61% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2020-12762

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-12762

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.28% 1.89% +1.61%
2 2025-12-28 0.17% 0.28% +0.11%
3 2025-12-27 — 0.17% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-12762

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2020-12762

OS Trackers for CVE-2020-12762

vendor priority summary link
alpine — CVE-2020-12762: 2 source package rows (json-c, libfastjson); 17 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 17, open 0. https://security.alpinelinux.org/vuln/CVE-2020-12762
debian not yet assigned CVE-2020-12762 not yet assigned priority: Debian including 2 source packages (json-c, libfastjson), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 10. https://security-tracker.debian.org/tracker/CVE-2020-12762
gentoo normal CVE-2020-12762: 1 GLSA(s) (202006-13), 1 atom(s) (dev-libs/json-c); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-12762
redhat medium — https://access.redhat.com/security/cve/CVE-2020-12762
suse high CVE-2020-12762 severity important: SUSE including 299 source package names (0.16.2:libjson-c3-0.13-3.3.1, 0.49.0.16.7:libjson-c3-0.13-3.3.1, …), 926 product×package rows across 410 product lines (Container bci/bci-init, Container caasp/v4/cilium, … (410 product lines)): Fixed 835, Known Affected 91. https://www.suse.com/security/cve/CVE-2020-12762/
ubuntu medium CVE-2020-12762 medium priority: Ubuntu including 1 source packages (json-c), 6 status rows across 6 suites (bionic, eoan, focal, trusty, upstream, xenial): released 5, needs-triage 1. https://ubuntu.com/security/CVE-2020-12762

Affected software / configurations for CVE-2020-12762

Vendor Product Version Raw CPE
json-c json-c < 0.15-20200726 cpe:2.3:a:json-c:json-c:*:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
canonical ubuntu_linux 12.04 cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:esm:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.10 cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
siemens sinec_ins — cpe:2.3:a:siemens:sinec_ins:-:*:*:*:*:*:*:*
siemens sinec_ins 1.0 cpe:2.3:a:siemens:sinec_ins:1.0:-:*:*:*:*:*:*
siemens sinec_ins 1.0 cpe:2.3:a:siemens:sinec_ins:1.0:sp1:*:*:*:*:*:*

References for CVE-2020-12762

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