CVE-2021-22925: curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl.
Noroxi assessment
Priority: Monitor (action score 23/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 5.3% (FIRST EPSS); higher than 92.7% of all records.
- 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.
- According to CISA the attack is automatable: targets can be found by mass scanning.
- Fixed version: curl (AlmaLinux:8) 7.61.1-22.el8; libcurl (AlmaLinux:8) 7.61.1-22.el8; libcurl-devel (AlmaLinux:8) 7.61.1-22.el8.
- Mentioned 6 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to curl (AlmaLinux:8) 7.61.1-22.el8; libcurl (AlmaLinux:8) 7.61.1-22.el8; libcurl-devel (AlmaLinux:8) 7.61.1-22.el8 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Aug 5, 2021
- Updated
- Oct 14, 2026
- EPSS
- 5.3% · 92th percentile
- CWE
- CWE-200
Report tools
Action score
23
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 5.3%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 5.3
- CNA · hackerone
- 5.3
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| haxx | curl | cpe:2.3:a:haxx:curl |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| netapp | cloud backup | cpe:2.3:a:netapp:cloud_backup |
| netapp | clustered data ontap | cpe:2.3:a:netapp:clustered_data_ontap |
| netapp | hci management node | cpe:2.3:a:netapp:hci_management_node |
| netapp | solidfire | cpe:2.3:a:netapp:solidfire |
| apple | mac os x | cpe:2.3:o:apple:mac_os_x |
| apple | macos | cpe:2.3:o:apple:macos |
| oracle | mysql server | cpe:2.3:a:oracle:mysql_server |
| oracle | peoplesoft enterprise peopletools | cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools |
| siemens | sinec infrastructure network services | cpe:2.3:a:siemens:sinec_infrastructure_network_services |
| siemens | sinema remote connect server | cpe:2.3:a:siemens:sinema_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.
- apple mac os x10.15.7
- apple macos11.0
- apple macos11.0.1
- apple macos11.1
- apple macos11.1.0
- apple macos11.2
- apple macos11.2.1
- apple macos11.3
- apple macos11.3.1
- apple macos11.4
- apple macos11.5
- fedoraproject fedora33
- haxx curl7.7 and later · before 7.78.0
- netapp cloud backupall versions
- netapp clustered data ontapall versions
- netapp h300e firmwareall versions
- netapp h300s firmwareall versions
- netapp h410s firmwareall versions
- netapp h500e firmwareall versions
- netapp h500s firmwareall versions
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.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | curl | before 7.61.1-22.el8 | 7.61.1-22.el8 |
| AlmaLinux:8 | libcurl | before 7.61.1-22.el8 | 7.61.1-22.el8 |
| AlmaLinux:8 | libcurl-devel | before 7.61.1-22.el8 | 7.61.1-22.el8 |
| AlmaLinux:8 | libcurl-minimal | before 7.61.1-22.el8 | 7.61.1-22.el8 |
| Alpine:v3.11 | curl | from 7.7 · before 7.67.0-r5 | 7.67.0-r5 |
| Alpine:v3.12 | curl | from 7.7 · before 7.78.0-r0 | 7.78.0-r0 |
| openSUSE:Leap 15.2 | curl | before 7.66.0-lp152.3.21.1 | 7.66.0-lp152.3.21.1 |
| openSUSE:Leap 15.2 | curl-mini | before 7.66.0-lp152.3.21.1 | 7.66.0-lp152.3.21.1 |
| openSUSE:Leap 15.3 | curl | before 7.66.0-4.22.1 | 7.66.0-4.22.1 |
| Red Hat:enterprise_linux:8::baseos | curl | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | curl-debuginfo | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | curl-debugsource | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | curl-minimal-debuginfo | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | libcurl | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | libcurl-debuginfo | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | libcurl-devel | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | libcurl-minimal | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Red Hat:enterprise_linux:8::baseos | libcurl-minimal-debuginfo | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| Rocky Linux:8 | curl | before 0:7.61.1-22.el8 | 0:7.61.1-22.el8 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | curl | before 7.60.0-3.47.1 | 7.60.0-3.47.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP2 | curl | before 7.66.0-4.22.1 | 7.66.0-4.22.1 |
| SUSE:Linux Enterprise Server 11-SECURITY | curl-openssl1 | before 7.37.0-70.71.1 | 7.37.0-70.71.1 |
| SUSE:Linux Enterprise Software Development Kit 12 SP5 | curl | before 7.60.0-11.23.1 | 7.60.0-11.23.1 |
| SUSE:OpenStack Cloud 9 | curl | before 7.60.0-4.25.1 | 7.60.0-4.25.1 |
Same product
haxx: all recordsOther 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 t51Plan
- 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-leak45Plan
Published before and after this one in the same product
- ← EarlierCVE-2021-22922Aug 5, 2021 · When curl is instructed to download content using the metalink feature, thecontents is verified against a hash provided in the metalink XML 27Monitor
- ← EarlierCVE-2021-22923Aug 5, 2021 · When curl is instructed to get content using the metalink feature, and a user name and password are used to download the metalink XML file, 22Monitor
- Later →CVE-2021-22926Aug 5, 2021 · libcurl-using applications can ask for a specific client certificate to be used in a transfer.35Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:curl | 7.61.1-22.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:libcurl | 7.61.1-22.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:libcurl-devel | 7.61.1-22.el8 · AlmaLinux:8 | Package registry (OSV) |
| almalinux:libcurl-minimal | 7.61.1-22.el8 · AlmaLinux:8 | Package registry (OSV) |
| alpine:curl | 7.67.0-r5 · Alpine:v3.11 | Package registry (OSV) |
| opensuse:curl | 7.66.0-lp152.3.21.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:curl-mini | 7.66.0-lp152.3.21.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:curl | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-debuginfo | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-debugsource | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-minimal-debuginfo | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-debuginfo | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-devel | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-minimal | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-minimal-debuginfo | 0:7.61.1-22.el8 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| rocky linux:curl | 0:7.61.1-22.el8 · Rocky Linux:8 | Package registry (OSV) |
| suse:curl | 7.60.0-4.25.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
| suse:curl-openssl1 | 7.37.0-70.71.1 · SUSE:Linux Enterprise Server 11-SECURITY | Package 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.
No history yet (it accumulates with the daily EPSS job).
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.
Credits
All researchersFinders, 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.
- TR-23-0118 · Mar 1, 2023(Curl Güvenlik Güncellemesi)
- TR-22-0222 · Mar 15, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0215 · Mar 11, 2022(Siemens Güvenlik Bildirimi)
- TR-22-0113 · Feb 4, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0097 · Jan 28, 2022(RedHat Güvenlik Güncellemesi)
- TR-21-0963 · Dec 2, 2021(RedHat Güvenlik Güncellemesi)
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
Weakness class (CWE)
CWE-200 · Exposure of Sensitive Information to an Unauthorized ActorCVSS 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.
The bug in code
The whole CWE-200 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
{
"permissions": ["tabs", "<all_urls>"],
"background": { "service_worker": "analytics.js" }
}Fixed
{
"permissions": ["activeTab"],
"host_permissions": ["https://yildiz.example/*"]
}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- ExcavationCAPEC-116likelihood: High · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- FootprintingCAPEC-169likelihood: High · Very Low
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- FingerprintingCAPEC-224likelihood: High · Very Low
- ICMP Echo Request PingCAPEC-285likelihood: Medium · Low
- TCP SYN ScanCAPEC-287Low
- Enumerate Mail Exchange (MX) RecordsCAPEC-290Low
ATT&CK techniques
- System Service DiscoveryT1007
- System Network Configuration DiscoveryT1016
- Remote System DiscoveryT1018
- System Owner/User DiscoveryT1033
- Masquerading: Match Legitimate Name or LocationT1036.005
- Network Service ScanningT1046
- System Network Connections DiscoveryT1049
- Process DiscoveryT1057
- Permission Groups DiscoveryT1069
- System Information DiscoveryT1082
- File and Directory DiscoveryT1083
- Account DiscoveryT1087
- Multi-Factor Authentication InterceptionT1111
- Peripheral Device DiscoveryT1120
- System Time DiscoveryT1124
- Access Token Manipulation:Token Impersonation/TheftT1134.001
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (13 more)Show less
- seclists.org/fulldisclosure/2021/Sep/40
- cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/
- security.gentoo.org/glsa/202212-01
- security.netapp.com/advisory/ntap-20210902-0003/
- support.apple.com/kb/HT212804
- support.apple.com/kb/HT212805
- www.oracle.com/security-alerts/cpujan2022.html
- www.oracle.com/security-alerts/cpuoct2021.html
- cert-portal.siemens.com/productcert/html/ssa-389290.html
- cert-portal.siemens.com/productcert/html/ssa-398330.html
- cert-portal.siemens.com/productcert/html/ssa-484086.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.