Curl
CVE-2021-22946
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Cryptographic step completeness
|
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.08%. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system. |
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Alert meAnalysisAI
A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (--ssl-reqd on the command line orCURLOPT_USE_SSL set to. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
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Technical ContextAI · show details
This vulnerability is classified under CWE-325. A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (--ssl-reqd on the command line orCURLOPT_USE_SSL set to CURLUSESSL_CONTROL or CURLUSESSL_ALL withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations withoutTLS contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network. Affected products include: Haxx Curl, Debian Debian Linux, Fedoraproject Fedora, Netapp Cloud Backup, Netapp Clustered Data Ontap.
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (--ssl-reqd on the command line orCURLOPT_USE_SSL set to CURLUSESSL_CONTROL or CURLUSESSL_ALL withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations withoutTLS contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)NVD
curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when
Stack-based buffer overflow in the Curl_sasl_create_digest_md5_message function in lib/curl_sasl.c in curl and libcurl 7
The sanitize_cookie_path function in cURL and libcurl 7.31.0 through 7.41.0 does not properly calculate an index, which
curl < 7.84.0 supports "chained" HTTP compression algorithms, meaning that a serverresponse can be compressed multiple t
When curl < 7.84.0 saves cookies, alt-svc and hsts data to local files, it makes the operation atomic by finalizing the
When doing HTTP(S) transfers, libcurl might erroneously use the read callback (`CURLOPT_READFUNCTION`) to ask for data t
Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that mig
A malicious server can serve excessive amounts of `Set-Cookie:` headers in a HTTP response to curl and curl < 7.84.0 sto
1. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack co
A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functional
A path traversal vulnerability exists in curl <8.0.0 SFTP implementation causes the tilde (~) character to be wrongly re
A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an atta
GitHub PoC
Exploit-DB