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CVE-2021-22925· NVD / CVE Program· CNA hackerone

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl.

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl. This rarely used option is used to send variable=content pairs toTELNET servers.Due to flaw in the option parser for sending `NEW_ENV` variables, libcurlcould be made to pass on uninitialized data from a stack based buffer to theserver. Therefore potentially revealing sensitive internal information to theserver using a clear-text network protocol.This could happen because curl did not call and use sscanf() correctly whenparsing the string provided by the application.

MediumCVSS 5.3 · v3.1—No exploit Fix available
Published
Aug 5, 2021
Updated
Jun 16, 2026
EPSS
4.9% · 92th percentile
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JSON

Action score

22

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 4.9%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Noroxi analysis

No Noroxi analysis for this record yet

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Affected systems

VendorProduct
haxxcurl
fedoraprojectfedora
netappcloud backup
netappclustered data ontap
netapphci management node
netappsolidfire
applemac os x
applemacos
oraclemysql server
oraclepeoplesoft enterprise peopletools
siemenssinec infrastructure network services
siemenssinema remote connect server

and 15 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • oracle mysql server5.7.0 and later · up to 5.7.35 inclusive
  • oracle mysql server8.0.0 and later · up to 8.0.26 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (hackerone). Independent of NVD's CPE analysis and usually ahead of it.

  • n/a https://github.com/curl/curl

    • curl 7.7 to and including 7.77.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8curlbefore 7.61.1-22.el87.61.1-22.el8
AlmaLinux:8libcurlbefore 7.61.1-22.el87.61.1-22.el8
AlmaLinux:8libcurl-develbefore 7.61.1-22.el87.61.1-22.el8
AlmaLinux:8libcurl-minimalbefore 7.61.1-22.el87.61.1-22.el8
Alpine:v3.11curlfrom 7.7 · before 7.67.0-r57.67.0-r5
Alpine:v3.12curlfrom 7.7 · before 7.78.0-r07.78.0-r0
openSUSE:Leap 15.2curlbefore 7.66.0-lp152.3.21.17.66.0-lp152.3.21.1
openSUSE:Leap 15.2curl-minibefore 7.66.0-lp152.3.21.17.66.0-lp152.3.21.1
openSUSE:Leap 15.3curlbefore 7.66.0-4.22.17.66.0-4.22.1
Red Hat:enterprise_linux:8::baseoscurlbefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoscurl-debuginfobefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoscurl-debugsourcebefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoscurl-minimal-debuginfobefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoslibcurlbefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoslibcurl-debuginfobefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoslibcurl-develbefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoslibcurl-minimalbefore 0:7.61.1-22.el80:7.61.1-22.el8
Red Hat:enterprise_linux:8::baseoslibcurl-minimal-debuginfobefore 0:7.61.1-22.el80:7.61.1-22.el8
Rocky Linux:8curlbefore 0:7.61.1-22.el80:7.61.1-22.el8
SUSE:Linux Enterprise High Performance Computing 15-ESPOScurlbefore 7.60.0-3.47.17.60.0-3.47.1
SUSE:Linux Enterprise Module for Basesystem 15 SP2curlbefore 7.66.0-4.22.17.66.0-4.22.1
SUSE:Linux Enterprise Server 11-SECURITYcurl-openssl1before 7.37.0-70.71.17.37.0-70.71.1
SUSE:Linux Enterprise Software Development Kit 12 SP5curlbefore 7.60.0-11.23.17.60.0-11.23.1
SUSE:OpenStack Cloud 9curlbefore 7.60.0-4.25.17.60.0-4.25.1

Same product

haxx: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-22901curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session t
    50Plan
  • CVE-2023-38039When curl retrieves an HTTP response, it stores the incoming headers so that they can be accessed later via the libcurl headers API.
    47Plan
  • CVE-2024-2398HTTP/2 push headers memory-leak
    45Plan
  • CVE-2019-5482Heap buffer overflow in the TFTP protocol handler in cURL 7.19.4 to 7.65.3.
    44Plan
  • CVE-2017-8817The FTP wildcard function in curl and libcurl before 7.57.0 allows remote attackers to cause a denial of service (out-of-bounds read and app
    42Plan
  • CVE-2017-8816The NTLM authentication feature in curl and libcurl before 7.57.0 on 32-bit platforms allows attackers to cause a denial of service (integer
    42Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
almalinux:curl7.61.1-22.el8 · AlmaLinux:8Package registry (OSV)
almalinux:libcurl7.61.1-22.el8 · AlmaLinux:8Package registry (OSV)
almalinux:libcurl-devel7.61.1-22.el8 · AlmaLinux:8Package registry (OSV)
almalinux:libcurl-minimal7.61.1-22.el8 · AlmaLinux:8Package registry (OSV)
alpine:curl7.67.0-r5 · Alpine:v3.11Package registry (OSV)
opensuse:curl7.66.0-lp152.3.21.1 · openSUSE:Leap 15.2Package registry (OSV)
opensuse:curl-mini7.66.0-lp152.3.21.1 · openSUSE:Leap 15.2Package registry (OSV)
red hat:curl0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:curl-debuginfo0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:curl-debugsource0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:curl-minimal-debuginfo0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:libcurl0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:libcurl-debuginfo0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:libcurl-devel0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:libcurl-minimal0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
red hat:libcurl-minimal-debuginfo0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseosPackage registry (OSV)
rocky linux:curl0:7.61.1-22.el8 · Rocky Linux:8Package registry (OSV)
suse:curl7.60.0-4.25.1 · SUSE:OpenStack Cloud 9Package registry (OSV)
suse:curl-openssl17.37.0-70.71.1 · SUSE:Linux Enterprise Server 11-SECURITYPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

CVSS vector

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

nvd-primary

Root cause

The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

json
{  "permissions": ["tabs", "<all_urls>"],  "background": { "service_worker": "analytics.js" }}

Fixed

json
{  "permissions": ["activeTab"],  "host_permissions": ["https://yildiz.example/*"]}

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records