CVE•Published 2021-12-18•Modified 2026-05-29•1 article on news•6 live references•NVD data
CVE-2021-45105Apache · Log4j
Vulnerability data via NVD (ingested)
CVSS v3.1
5.9
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS percentile
99
Exploit Prediction Scoring System · top 1% of all CVEs
Weaknesses (CWE)
Description
Apache Log4j2 versions 2.0-alpha1 through 2.16.0 (excluding 2.12.3 and 2.3.1) did not protect from uncontrolled recursion from self-referential lookups. This allows an attacker with control over Thread Context Map data to cause a denial of service when a crafted string is interpreted. This issue was fixed in Log4j 2.17.0, 2.12.3, and 2.3.1.
Timeline
Published 2021-12-18
Modified 2026-05-29
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
Shodan · vuln tag0 hosts
vuln:CVE-2021-45105Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Apache Log4j"All exposed Apache Log4j instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Log4j"HTTP body or banner mentions "Log4j" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2021-45105Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2021-45105Censys host search filtered to this CVE id.
grep.app
CVE-2021-45105Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2021-45105GitHub code search for direct mentions.
Google dork
"CVE-2021-45105" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.