CVE•Published 2021-09-23•Modified 2026-10-14•1 article on news•5 live references•NVD data
CVE-2021-22945Haxx · Libcurl
Vulnerability data via NVD (ingested)
CVSS v3.1
9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS percentile
94
Exploit Prediction Scoring System · top 6% of all CVEs
Weaknesses (CWE)
Description
When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed memory area and both use that again in a subsequent call to send data and also free it *again*.
Timeline
Published 2021-09-23
Modified 2026-10-14
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-2021-22945Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Haxx Libcurl"All exposed Haxx Libcurl instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Libcurl"HTTP body or banner mentions "Libcurl" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2021-22945Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2021-22945Censys host search filtered to this CVE id.
grep.app
CVE-2021-22945Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2021-22945GitHub code search for direct mentions.
Google dork
"CVE-2021-22945" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.