CVE-2021-22898

Exp

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.

Published: 2021-06-11 Last update: 2026-04-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-22898 is rated Exploit Available (50/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.13%). 2 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-22898

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-22898

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 0.18% 0.13% -0.05%
2 2026-03-01 0.13% 0.18% +0.05%
3 2026-02-04 — 0.13% —

Full EPSS history (46 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22898

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.1 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 1.4 [email protected]
3.1 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0
2.6 2.0 LOW
AV:N/AC:H/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 2.9 [email protected]

Weakness enumeration for CVE-2021-22898

OS Trackers for CVE-2021-22898

vendor priority summary link
alpine — CVE-2021-22898: 1 source package rows (curl); 130 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 120. https://security.alpinelinux.org/vuln/CVE-2021-22898
debian not yet assigned CVE-2021-22898 not yet assigned priority: Debian including 1 source packages (curl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-22898
gentoo high CVE-2021-22898: 1 GLSA(s) (202105-36), 1 atom(s) (net-misc/curl); latest impact high. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2021-22898
redhat low — https://access.redhat.com/security/cve/CVE-2021-22898
suse medium CVE-2021-22898 severity moderate: SUSE including 419 source package names (0.1.0:libcurl4-7.60.0-3.42.1, 0.1.75:libcurl4-7.60.0-3.42.1, …), 681 product×package rows across 220 product lines (Container bci/bci-init, Container bci/dotnet-aspnet, … (220 product lines)): Fixed 548, Known Affected 133. https://www.suse.com/security/cve/CVE-2021-22898/
ubuntu low CVE-2021-22898 low priority: Ubuntu including 1 source packages (curl), 11 status rows across 11 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): released 10, ignored 1. https://ubuntu.com/security/CVE-2021-22898

Affected software / configurations for CVE-2021-22898

Vendor Product Version Raw CPE
haxx curl >= 7.7, <= 7.76.1 cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
oracle communications_cloud_native_core_binding_support_function 1.11.0 cpe:2.3:a:oracle:communications_cloud_native_core_binding_support_function:1.11.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_function_cloud_native_environment 1.10.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:1.10.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_repository_function 1.15.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:1.15.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_repository_function 1.15.1 cpe:2.3:a:oracle:communications_cloud_native_core_network_repository_function:1.15.1:*:*:*:*:*:*:*
oracle communications_cloud_native_core_network_slice_selection_function 1.8.0 cpe:2.3:a:oracle:communications_cloud_native_core_network_slice_selection_function:1.8.0:*:*:*:*:*:*:*
oracle communications_cloud_native_core_service_communication_proxy 1.15.0 cpe:2.3:a:oracle:communications_cloud_native_core_service_communication_proxy:1.15.0:*:*:*:*:*:*:*
oracle essbase < 11.1.2.4.047 cpe:2.3:a:oracle:essbase:*:*:*:*:*:*:*:*
oracle essbase >= 21.0, < 21.3 cpe:2.3:a:oracle:essbase:*:*:*:*:*:*:*:*
oracle mysql_server < 5.7.34 cpe:2.3:a:oracle:mysql_server:*:*:*:*:*:*:*:*
oracle mysql_server >= 8.0.15, < 8.0.25 cpe:2.3:a:oracle:mysql_server:*:*:*:*:*:*:*:*
siemens sinec_infrastructure_network_services < 1.0.1.1 cpe:2.3:a:siemens:sinec_infrastructure_network_services:*:*:*:*:*:*:*:*
splunk universal_forwarder >= 8.2.0, < 8.2.12 cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
splunk universal_forwarder >= 9.0.0, < 9.0.6 cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
splunk universal_forwarder 9.1.0 cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:*

References for CVE-2021-22898

URL Tags
http://www.openwall.com/lists/oss-security/2021/07/21/4 Mailing List Patch Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf Patch Third Party Advisory
https://curl.se/docs/CVE-2021-22898.html Exploit Patch Vendor Advisory
https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde Patch Third Party Advisory
https://hackerone.com/reports/1176461 Exploit Issue Tracking Patch Third Party Advisory
https://lists.apache.org/thread.html/rc713534b10f9daeee2e0990239fa407e2118e4aa9e88a7041177497c%40%3Cissues.guacamole.apache.org%3E Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html Mailing List Third 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/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/POOC3UV7V6L4CJ5KA2PTWTNUV5Y72T3Q/ Mailing List Third Party Advisory
https://www.debian.org/security/2022/dsa-5197 Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Patch Third Party Advisory
cvelogic Threat Intelligence