CVE•Published 2021-06-11•Modified 2026-10-14•0 articles on news•6 live references•NVD data

CVE-2021-22898Haxx · Curl

Vulnerability data via NVD (ingested)

CVSS v3.1

3.1

LOW

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

EPSS percentile

Exploit Prediction Scoring System · top 9% of all CVEs

Weaknesses (CWE)

CWE-200Exposure of Sensitive Information to an Unauthorized Actor CWE-909Missing Initialization of Resource

Description

curl 7.7 through 7.76.1 suffers from an information disclosure when the `-t` command line option, known as `CURLOPT_TELNETOPTIONS` in libcurl, is used to send variable=content pairs to TELNET servers. Due to a flaw in the option parser for sending NEW_ENV variables, libcurl could be made to pass on uninitialized data from a stack based buffer to the server, resulting in potentially revealing sensitive internal information to the server using a clear-text network protocol.

Timeline

Published 2021-06-11

Modified 2026-10-14

External references

NVD MITRE Exploit-DB GitHub PoC trickest/cve VulnCheck

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 tag3 hosts

vuln:CVE-2021-22898

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Haxx Curl"

All exposed Haxx Curl instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Curl"

HTTP body or banner mentions "Curl" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2021-22898