← Vulnerability feed

Vulnerability record · CVE-2021-22898 · published 11 June 2021

CVE-2021-22898: Haxx curl information exposure vulnerability

Haxx · Curl

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.

3.1 CVSS 3.1 Low EPSS 4.5% · top 8.6% CWE-200 · Information exposureCWE-909 · CWE-909
3.1CVSS 3.1 base score, v2 2.6
4.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
12Affected product versions listed by NVD
29References, 4 tagged exploit
14 Oct 2026Last modified by NVD

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.

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

Affected products

12 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/07/21/4 Mailing ListPatchThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://curl.se/docs/CVE-2021-22898.html ExploitPatchVendor Advisory
https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde PatchThird Party Advisory
https://hackerone.com/reports/1176461 ExploitIssue TrackingPatchThird Party Advisory
https://lists.apache.org/thread.html/rc713534b10f9daeee2e0990239fa407e2118e4aa9e88a7041177497c%40%3Cissues.guacamole.apa Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4 Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/POOC3UV7V6L4CJ5KA2PTWTN Mailing ListThird Party Advisory
https://www.debian.org/security/2022/dsa-5197 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/07/21/4 Mailing ListPatchThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://curl.se/docs/CVE-2021-22898.html ExploitPatchVendor Advisory
https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde PatchThird Party Advisory
https://hackerone.com/reports/1176461 ExploitIssue TrackingPatchThird Party Advisory
https://lists.apache.org/thread.html/rc713534b10f9daeee2e0990239fa407e2118e4aa9e88a7041177497c%40%3Cissues.guacamole.apa Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4 Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/POOC3UV7V6L4CJ5KA2PTWTN Mailing ListThird Party Advisory
https://www.debian.org/security/2022/dsa-5197 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-398330.html

Track CVE-2021-22898 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

10.0CVE-2025-32433Erlang/OTP SSH server missing authentication allows remote code executionErlang/OTP SSH servers before OTP-27.3.3, OTP-26.2.5.11 and OTP-25.3.2.20 mishandle SSH protocol messages, letting an unauthenticated attacker execut…KEVEPSS 99%analysed10.0CVE-2025-24201Apple WebKit out-of-bounds write allows sandbox escapeCVE-2025-24201 is an out-of-bounds write in Apple's WebKit that was addressed with improved checks. Maliciously crafted web content may break out of …KEVEPSS 3.8%analysed10.0CVE-2022-22947Spring Cloud Gateway Actuator endpoint code injectionSpring Cloud Gateway versions before 3.1.1+ and 3.0.7+ allow code injection when the Gateway Actuator endpoint is enabled, exposed and unsecured. A c…KEVEPSS 98%analysed10.0CVE-2021-44228Apache Log4j2 JNDI lookup remote code executionApache Log4j2 versions 2.0-beta9 through 2.15.0 (excluding 2.12.2, 2.12.3, and 2.3.1) do not protect against attacker-controlled LDAP and other JNDI …KEVEPSS 100%analysed10.0CVE-2015-3306ProFTPD mod_copy arbitrary file read and writeThe mod_copy module in ProFTPD 1.3.5 fails to restrict the SITE CPFR and SITE CPTO commands, letting remote attackers copy arbitrary files on the ser…KEVEPSS 99%analysed9.8CVE-2026-24061GNU Inetutils telnetd argument injection allows remote auth bypasstelnetd in GNU Inetutils through 2.7 fails to sanitize the USER environment variable, so a value such as "-f root" is passed as an argument to login …KEVEPSS 99%analysed9.8CVE-2025-39682Linux kernel TLS zero-length record handling flaw on rx_listThe Linux kernel TLS receive path mishandles zero-length records that arrive from the rx_list, breaking the assumption that a record type change cann…KEVEPSS 2.9%analysed9.8CVE-2025-24813Apache Tomcat Default Servlet path equivalence enables RCE and file disclosureApache Tomcat mishandles path equivalence for names containing an internal dot, letting a remote unauthenticated attacker write files through the Def…KEVEPSS 100%analysed

Source: NIST National Vulnerability Database (record CVE-2021-22898), CISA KEV, FIRST EPSS (scores of 2026-10-15). This page is refreshed as NVD updates the record.