CVE-2021-42836

Exp

GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack.

Published: 2021-10-22 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-42836 is rated Exploit Available (57.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.16%). 2 public exploit reference(s) are indexed (Exploit-DB). 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-2021-42836

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-2021-42836

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 2025-11-21 0.82% 0.16% -0.66%
2 2025-11-18 0.18% 0.82% +0.64%
3 2025-09-12 — 0.18% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-42836

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-42836

GitHub Security Advisory for CVE-2021-42836

GHSA-ppj4-34rq-v8j9 · Severity: high · Ecosystem: go — github.com/tidwall/gjson Vulnerable to REDoS attack

OS Trackers for CVE-2021-42836

vendor priority summary link
debian not yet assigned CVE-2021-42836 not yet assigned priority: Debian including 1 source packages (golang-github-tidwall-gjson), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2021-42836
ubuntu medium CVE-2021-42836 medium priority: Ubuntu including 1 source packages (golang-github-tidwall-gjson), 14 status rows across 14 suites (focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): ignored 9, needs-triage 5. https://ubuntu.com/security/CVE-2021-42836

Affected software / configurations for CVE-2021-42836

Vendor Product Version Raw CPE
gjson_project gjson < 1.9.3 cpe:2.3:a:gjson_project:gjson:*:*:*:*:*:*:*:*

References for CVE-2021-42836

cvelogic Threat Intelligence