# What is CVE-2021-22924?

> CVE-2021-22924 is a low-severity flaw (CVSS 3.7) in Libcurl from Haxx, published on 5 August 2021. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 6.3%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-22924

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **Precursor Intelligence risk score:** 47 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** Low (CVSS 3.7 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 6.3% (latest exploit-likelihood forecast)
- **Published:** 5 August 2021
- **Record last updated:** 9 June 2025
- **Main product:** Libcurl from Haxx
- **Affected products:** 33

## What is CVE-2021-22924? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read some data.

### The official description

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.

### What kind of flaw is it?

- CWE-20: Improper Input Validation
- CWE-706: Use of Incorrectly-Resolved Name or Reference

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Hard: conditions must line up
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read some data

Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N`

## Is CVE-2021-22924 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 6.3%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 6.3%, 6.3%, 6.3%, 6.3%, 6.3%, 6.3%, 6.3%.

### Timeline

- 5 August 2021: Published
- 9 June 2025: Record last updated

### How Precursor Intelligence ranks it

CVE-2021-22924 scores **47 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2021-22924?

The published record lists 33 products. Versions are as published: "7.10.4 to before 7.77.0" means from 7.10.4 up to, but not including, 7.77.0.

- [Libcurl](https://www.precursorintelligence.com/product/haxx/libcurl) by [Haxx](https://www.precursorintelligence.com/vendors/haxx) (Application): 7.10.4 to before 7.77.0
- [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 9.0, 10.0, 11.0
- [Peoplesoft Enterprise Peopletools](https://www.precursorintelligence.com/product/oracle/peoplesoft_enterprise_peopletools) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): 8.57, 8.58, 8.59
- [Universal Forwarder](https://www.precursorintelligence.com/product/splunk/universal_forwarder) by [Splunk](https://www.precursorintelligence.com/vendors/splunk) (Application): 8.2.0 to before 8.2.12, 9.0.0 to before 9.0.6, 9.1.0
- [Mysql Server](https://www.precursorintelligence.com/product/oracle/mysql_server) by [Oracle](https://www.precursorintelligence.com/vendors/oracle) (Application): 5.7.0 to 5.7.36, 8.0.0 to 8.0.26
- [Cloud Backup](https://www.precursorintelligence.com/product/netapp/cloud_backup) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Clustered Data Ontap](https://www.precursorintelligence.com/product/netapp/clustered_data_ontap) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Fedora](https://www.precursorintelligence.com/product/fedoraproject/fedora) by [Fedoraproject](https://www.precursorintelligence.com/vendors/fedoraproject) (Operating system): 33
- Logo! Cmr2020 Firmware by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): all versions
- Logo! Cmr2040 Firmware by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): all versions
- [Ruggedcomrm 1224 Lte Firmware](https://www.precursorintelligence.com/product/siemens/ruggedcomrm_1224_lte_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M804pb Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m804pb_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M812-1 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m812-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M816-1 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m816-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M826-2 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m826-2_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M874-2 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m874-2_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M874-3 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m874-3_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M876-3 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m876-3_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance M876-4 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_m876-4_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance Mum856-1 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_mum856-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Scalance S615 Firmware](https://www.precursorintelligence.com/product/siemens/scalance_s615_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 7.1
- [Simatic Cp 1543-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_cp_1543-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.0.22
- [Simatic Cp 1545-1 Firmware](https://www.precursorintelligence.com/product/siemens/simatic_cp_1545-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 1.1
- [Simatic RTU 3041c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rtu_3041c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 5.0.14
- [Simatic Rtu3010c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rtu3010c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 5.0.14
- [Simatic Rtu3030c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rtu3030c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 5.0.14
- [Simatic Rtu3031c Firmware](https://www.precursorintelligence.com/product/siemens/simatic_rtu3031c_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 5.0.14
- [Sinec Infrastructure Network Services](https://www.precursorintelligence.com/product/siemens/sinec_infrastructure_network_services) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 1.0.1.1
- [Sinema Remote Connect](https://www.precursorintelligence.com/product/siemens/sinema_remote_connect) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 3.1
- [Sinema Remote Connect Server](https://www.precursorintelligence.com/product/siemens/sinema_remote_connect_server) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Application): before 3.1
- [Siplus Net Cp 1543-1 Firmware](https://www.precursorintelligence.com/product/siemens/siplus_net_cp_1543-1_firmware) by [Siemens](https://www.precursorintelligence.com/vendors/siemens) (Operating system): before 3.0.22
- Solidfire & Hci Management Node by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Solidfire Baseboard Management Controller Firmware](https://www.precursorintelligence.com/product/netapp/solidfire_baseboard_management_controller_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified

## How do I fix CVE-2021-22924?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf) (Patch, Third-party advisory)
- [hackerone.com](https://hackerone.com/reports/1223565) (Exploit, Issue tracking, Patch, Third-party advisory)
- [oracle.com](https://www.oracle.com/security-alerts/cpujan2022.html) (Patch, Third-party advisory)
- [oracle.com](https://www.oracle.com/security-alerts/cpuoct2021.html) (Patch, Third-party advisory)
- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf) (Third-party advisory)
- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf) (Third-party advisory)
- [lists.apache.org](https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cdev.kafka.apache.org%3E) (Mailing list, Third-party advisory)
- [lists.apache.org](https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cusers.kafka.apache.org%3E) (Mailing list, Third-party advisory)
- [lists.apache.org](https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cdev.kafka.apache.org%3E) (Mailing list, Third-party advisory)
- [lists.apache.org](https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cusers.kafka.apache.org%3E) (Mailing list, Third-party advisory)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2021/08/msg00017.html) (Mailing list, Third-party advisory)
- [lists.debian.org](https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html) (Mailing list, Third-party advisory)
- [lists.fedoraproject.org](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4PJEC6CF7V/) (Mailing list, Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20210902-0003/) (Third-party advisory)
- [debian.org](https://www.debian.org/security/2022/dsa-5197) (Third-party advisory)

## Questions

### What is CVE-2021-22924?

CVE-2021-22924 is a low-severity flaw in Libcurl from Haxx, published on 5 August 2021. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read some data.

### How serious is CVE-2021-22924?

It scores 3.7 out of 10 on the CVSS severity scale, which is low. Our risk score for CVE-2021-22924 is 47 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2021-22924 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 6.3%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2021-22924 affect?

For Libcurl from Haxx: 7.10.4 to before 7.77.0. The record lists 33 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2021-22924?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2021-22924 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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