CVE-2021-22876: curl 7.1.1 to and including 7.75.0 is vulnerable to an "Exposure of Private Personal Information to an Unauthorized Actor" by leaking creden
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 92.6% 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 7.1.1 to and including 7.75.0 is vulnerable to an "Exposure of Private Personal Information to an Unauthorized Actor" by leaking credentials in the HTTP Referer: header. libcurl does not strip off user credentials from the URL when automatically populating the Referer: HTTP request header field in outgoing HTTP requests, and therefore risks leaking sensitive data to the server that is the target of the second HTTP request.
- Published
- Apr 1, 2021
- Updated
- Oct 14, 2026
- EPSS
- 5.3% · 92th percentile
- CWE
- CWE-359
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 | libcurl | cpe:2.3:a:haxx:libcurl |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| netapp | hci management node | cpe:2.3:a:netapp:hci_management_node |
| netapp | solidfire | cpe:2.3:a:netapp:solidfire |
| netapp | hci compute node | cpe:2.3:h:netapp:hci_compute_node |
| netapp | hci storage node | cpe:2.3:h:netapp:hci_storage_node |
| broadcom | fabric operating system | cpe:2.3:o:broadcom:fabric_operating_system |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| siemens | sinec infrastructure network services | cpe:2.3:a:siemens:sinec_infrastructure_network_services |
| oracle | communications billing and revenue management | cpe:2.3:a:oracle:communications_billing_and_revenue_management |
| oracle | essbase | cpe:2.3:a:oracle:essbase |
| splunk | universal forwarder | cpe:2.3:a:splunk:universal_forwarder |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- broadcom fabric operating systemall versions
- debian debian linux9.0
- fedoraproject fedora32
- fedoraproject fedora33
- fedoraproject fedora34
- haxx libcurl7.1.1 and later · up to 7.75.0 inclusive
- netapp hci compute nodeall versions
- netapp hci management nodeall versions
- netapp hci storage nodeall versions
- netapp solidfireall versions
- oracle communications billing and revenue management12.0.0.3.0
- oracle essbase21.2
- siemens sinec infrastructure network servicesbefore 1.0.1.1
- splunk universal forwarder8.2.0 and later · before 8.2.12
- splunk universal forwarder9.0.0 and later · before 9.0.6
- splunk universal forwarder9.1.0
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
- 7.1.1 to and including 7.75.0affected
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:v3.12 | curl | before 7.76.0-r0 | 7.76.0-r0 |
| Debian:10 | curl | before 7.64.0-4+deb10u2 | 7.64.0-4+deb10u2 |
| Debian:12 | curl | before 7.74.0-1.2 | 7.74.0-1.2 |
| Debian:9 | curl | before 7.52.1-5+deb9u14 | 7.52.1-5+deb9u14 |
| openSUSE:Leap 15.2 | curl | before 7.66.0-lp152.3.15.1 | 7.66.0-lp152.3.15.1 |
| openSUSE:Leap 15.2 | curl-mini | before 7.66.0-lp152.3.15.1 | 7.66.0-lp152.3.15.1 |
| 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 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24 | before 0:1-18.jbcs.el7 | 0:1-18.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-apr | before 0:1.6.3-105.jbcs.el7 | 0:1.6.3-105.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-apr-debuginfo | before 0:1.6.3-105.jbcs.el7 | 0:1.6.3-105.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-apr-devel | before 0:1.6.3-105.jbcs.el7 | 0:1.6.3-105.jbcs.el7 |
| Red Hat:jboss_core_services:1::el7 | jbcs-httpd24-apr-util | before 0:1.6.1-82.jbcs.el7 | 0:1.6.1-82.jbcs.el7 |
+96
Same product
haxx: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-38545This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy
handshake.63This week
- CVE-2019-5436A heap buffer overflow in the TFTP receiving code allows for DoS or arbitrary code execution in libcurl versions 7.19.4 through 7.64.1.46Plan
- CVE-2019-3822libcurl versions from 7.36.0 to before 7.64.0 are vulnerable to a stack-based buffer overflow.43Plan
Published before and after this one in the same product
- ← EarlierCVE-2020-8285Dec 14, 2020 · curl 7.21.0 to and including 7.73.0 is vulnerable to uncontrolled recursion due to a stack overflow issue in FTP wildcard match parsing.33Monitor
- ← EarlierCVE-2020-8286Dec 14, 2020 · curl 7.41.0 through 7.73.0 is vulnerable to an improper check for certificate revocation due to insufficient verification of the OCSP respon31Monitor
- Later →CVE-2021-22890Apr 1, 2021 · curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of T15Monitor
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 | 7.76.0-r0 · Alpine:v3.12 | Package registry (OSV) |
| debian:curl | 7.74.0-1.2 · Debian:12 | Package registry (OSV) |
| opensuse:curl | 7.66.0-lp152.3.15.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| opensuse:curl-mini | 7.66.0-lp152.3.15.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| red hat:jbcs-httpd24 | 0:1-18.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr | 0:1.6.3-105.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-debuginfo | 0:1.6.3-105.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-devel | 0:1.6.3-105.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-debuginfo | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-devel | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-ldap | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-mysql | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-nss | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-odbc | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| red hat:jbcs-httpd24-apr-util-openssl | 0:1.6.1-82.jbcs.el7 · Red Hat:jboss_core_services:1::el7 | Package registry (OSV) |
| rocky linux:curl | 0:7.61.1-22.el8 · Rocky Linux:8 | Package registry (OSV) |
| suse:curl | 7.66.0-4.14.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP2 | Package registry (OSV) |
| suse:curl-openssl1 | 7.37.0-70.60.1 · 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-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)
- TR-21-0574 · Jul 13, 2021(IBM Güvenlik Bülteni)
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-359 · Exposure of Private Personal 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
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (10 more)Show less
- curl.se/docs/CVE-2021-22876.html
- lists.debian.org/debian-lts-announce/2021/05/msg00019.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
- security.gentoo.org/glsa/202105-36
- security.netapp.com/advisory/ntap-20210521-0007/
- www.oracle.com//security-alerts/cpujul2021.html
- cert-portal.siemens.com/productcert/html/ssa-389290.html
- cert-portal.siemens.com/productcert/html/ssa-398330.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.