CVE-2021-22924: libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse, if one of them matches the setup.Due to err
Noroxi assessment
Priority: Monitor (action score 16/100)
- Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
- Probability of exploitation in the next 30 days: 6.2% (FIRST EPSS); higher than 93.6% 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. Special conditions such as timing or configuration are required.
- Fixed version: curl (Alpine:v3.12) 7.78.0-r0; curl (Debian:10) 7.64.0-4+deb10u3; curl (Debian:11) 7.74.0-1.3+deb11u2.
- Mentioned 5 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to curl (Alpine:v3.12) 7.78.0-r0; curl (Debian:10) 7.64.0-4+deb10u3; curl (Debian:11) 7.74.0-1.3+deb11u2 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
libcurl keeps previously used connections in a connection pool for subsequenttransfers to reuse, if one of them matches the setup.Due to errors in the logic, the config matching function did not take 'issuercert' into account and it compared the involved paths *case insensitively*,which could lead to libcurl reusing wrong connections.File paths are, or can be, case sensitive on many systems but not all, and caneven vary depending on used file systems.The comparison also didn't include the 'issuer cert' which a transfer can setto qualify how to verify the server certificate.
- Published
- Aug 5, 2021
- Updated
- Oct 14, 2026
- EPSS
- 6.2% · 93th percentile
- CWE
- CWE-20
Report tools
Action score
16
Monitor
Low priority for now.
- CVSS
- 14 / 40 · 3.7 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 2 / 30 · 6.2%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 3.7
- CNA · hackerone
- 3.7
- 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
- Proof of concept exists, no weaponized module
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
Running WordPress? Scan your site free with WP Lens
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 |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| netapp | cloud backup | cpe:2.3:a:netapp:cloud_backup |
| netapp | clustered data ontap | cpe:2.3:a:netapp:clustered_data_ontap |
| netapp | solidfire & hci management node | cpe:2.3:a:netapp:solidfire_&_hci_management_node |
| netapp | solidfire baseboard management controller firmware | cpe:2.3:o:netapp:solidfire_baseboard_management_controller_firmware |
| 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 |
| siemens | logo! cmr2040 firmware | cpe:2.3:o:siemens:logo!_cmr2040_firmware |
and 41 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- debian debian linux10.0
- debian debian linux11.0
- debian debian linux9.0
- fedoraproject fedora33
- haxx libcurl7.10.4 and later · before 7.77.0
- netapp cloud backupall versions
- netapp clustered data ontapall versions
- netapp solidfire & hci management nodeall versions
- netapp solidfire baseboard management controller firmwareall versions
- oracle mysql server5.7.0 and later · up to 5.7.36 inclusive
- oracle mysql server8.0.0 and later · up to 8.0.26 inclusive
- oracle peoplesoft enterprise peopletools8.57
- oracle peoplesoft enterprise peopletools8.58
- oracle peoplesoft enterprise peopletools8.59
- siemens logo! cmr2020 firmwareall versions
- siemens logo! cmr2040 firmwareall versions
- siemens ruggedcomrm 1224 lte firmwarebefore 7.1
- siemens scalance m804pb firmwarebefore 7.1
- siemens scalance m812-1 firmwarebefore 7.1
- siemens scalance m816-1 firmwarebefore 7.1
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 7.10.4 to and include curl 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 |
|---|---|---|---|
| Alpine:v3.12 | curl | before 7.78.0-r0 | 7.78.0-r0 |
| Debian:10 | curl | before 7.64.0-4+deb10u3 | 7.64.0-4+deb10u3 |
| Debian:11 | curl | before 7.74.0-1.3+deb11u2 | 7.74.0-1.3+deb11u2 |
| Debian:12 | curl | before 7.79.1-1 | 7.79.1-1 |
| Debian:9 | curl | before 7.52.1-5+deb9u15 | 7.52.1-5+deb9u15 |
| 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 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | curl-debuginfo | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | curl-debugsource | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | curl-minimal-debuginfo | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | libcurl | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | libcurl-debuginfo | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | libcurl-devel | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | libcurl-minimal | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:enterprise_linux:8::baseos | libcurl-minimal-debuginfo | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| Red Hat:rhel_dotnet:3.1::el7 | rh-dotnet31-curl | before 0:7.61.1-22.el7_9 | 0:7.61.1-22.el7_9 |
| Red Hat:rhel_dotnet:3.1::el7 | rh-dotnet31-curl-debuginfo | before 0:7.61.1-22.el7_9 | 0:7.61.1-22.el7_9 |
| Red Hat:rhel_dotnet:3.1::el7 | rh-dotnet31-libcurl | before 0:7.61.1-22.el7_9 | 0:7.61.1-22.el7_9 |
| Red Hat:rhel_dotnet:3.1::el7 | rh-dotnet31-libcurl-devel | before 0:7.61.1-22.el7_9 | 0:7.61.1-22.el7_9 |
| Rocky Linux:8 | curl | before 0:7.61.1-18.el8_4.1 | 0:7.61.1-18.el8_4.1 |
| 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 |
+3
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.62This 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-2021-22876Apr 1, 2021 · 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 creden23Monitor
- ← EarlierCVE-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
- Later →CVE-2021-22945Sep 23, 2021 · When sending data to an MQTT server, libcurl <= 7.73.0 and 7.78.0 could in some circumstances erroneously keep a pointer to an already freed38Monitor
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 |
|---|---|---|
| alpine:curl | 7.78.0-r0 · Alpine:v3.12 | Package registry (OSV) |
| debian:curl | 7.79.1-1 · Debian:12 | 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 | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-debuginfo | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-debugsource | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:curl-minimal-debuginfo | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-debuginfo | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-devel | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-minimal | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:libcurl-minimal-debuginfo | 0:7.61.1-18.el8_4.1 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:rh-dotnet31-curl | 0:7.61.1-22.el7_9 · Red Hat:rhel_dotnet:3.1::el7 | Package registry (OSV) |
| red hat:rh-dotnet31-curl-debuginfo | 0:7.61.1-22.el7_9 · Red Hat:rhel_dotnet:3.1::el7 | Package registry (OSV) |
| red hat:rh-dotnet31-libcurl | 0:7.61.1-22.el7_9 · Red Hat:rhel_dotnet:3.1::el7 | Package registry (OSV) |
| rocky linux:curl | 0:7.61.1-18.el8_4.1 · 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
Proof of concept available
A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.
Evidence
- Proof-of-concept repository on GitHub ×1
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:0 | 2022-04-30 |
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.
- Published
- First PoC+267 d
- TodayNov 10, 2026+1923 d
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-22-0351 · May 13, 2022(Siemens Güvenlik Bildirimi)
- TR-22-0222 · Mar 15, 2022(RedHat Güvenlik Güncellemesi)
- TR-22-0215 · Mar 11, 2022(Siemens Güvenlik Bildirimi)
- TR-21-0803 · Oct 5, 2021(IBM Güvenlik Bülteni)
- TR-21-0767 · Sep 22, 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.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:N/AC:H/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.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (17 more)Show less
- cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf
- cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf
- lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cdev.kafka.apache.org%3E
- lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cusers.kafka.apache.org%3E
- lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cdev.kafka.apache.org%3E
- lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cusers.kafka.apache.org%3E
- lists.debian.org/debian-lts-announce/2021/08/msg00017.html
- lists.debian.org/debian-lts-announce/2022/08/msg00017.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/
- security.netapp.com/advisory/ntap-20210902-0003/
- www.debian.org/security/2022/dsa-5197
- 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
- cert-portal.siemens.com/productcert/html/ssa-732250.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.