Vulnerability Report

CVE-2021-22924

Title: Incorrect Connection Reuse in libcurl

Security Bypass

Proof Of Concept

No public PoC currently indexed for CVE-2021-22924.

CWE Category CWE-706
Published Date Aug 05, 2021
Modified Date Jun 09, 2025
Exploit Status Not Found
Score 3.7 CVSS v3.1
Exploit Probability (EPSS)
6.27%

Vulnerability Summary

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 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.

Impacted Vendors

L
libcurl 1
O
oracle 2
M
mysql 1
N
netapp 3
S
siemens 23
S
splunk 1
H
haxx 1

Reference Links

https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf https://hackerone.com/reports/1223565 https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cdev.kafka.apache.org%3E https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cusers.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cdev.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cusers.kafka.apache.org%3E https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/ https://security.netapp.com/advisory/ntap-20210902-0003/ https://www.debian.org/security/2022/dsa-5197 https://www.oracle.com/security-alerts/cpujan2022.html https://www.oracle.com/security-alerts/cpuoct2021.html https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf https://hackerone.com/reports/1223565 https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cdev.kafka.apache.org%3E https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cusers.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cdev.kafka.apache.org%3E https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cusers.kafka.apache.org%3E https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/ https://security.netapp.com/advisory/ntap-20210902-0003/ https://www.debian.org/security/2022/dsa-5197 https://www.oracle.com/security-alerts/cpujan2022.html https://www.oracle.com/security-alerts/cpuoct2021.html
CVSS v3.1
Source Entity [email protected]
Severity LOW
3.7
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS v3.1
Source Entity 134c704f-9b21-4f2e-91b3-4a467353bcc0
Severity LOW
3.7
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS v2.0
Source Entity [email protected]
Severity MEDIUM
4.3
Access Vector
N/A
Authentication
N/A
RAW VECTOR AV:N/AC:M/Au:N/C:P/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2021-22924 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data or affected products updated.

PUBLISHED

Vulnerability first announced in NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected Stack

No specific products linked.