# What is CVE-2021-22926?

> CVE-2021-22926 is a high-severity flaw (CVSS 7.5) in Curl 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 15%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-22926

## At a glance

- **Verdict:** Fix this soon. Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
- **Precursor Intelligence risk score:** 53 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 7.5 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:** 15% (latest exploit-likelihood forecast)
- **Published:** 5 August 2021
- **Record last updated:** 27 March 2024
- **Main product:** Curl from Haxx
- **Affected products:** 26

## What is CVE-2021-22926? 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 take it offline.

### The official description

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

### What kind of flaw is it?

- CWE-295: Improper Certificate Validation

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Easy: no special conditions
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can take it offline

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

## Is CVE-2021-22926 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 15%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 9.8%, 9.8%, 9.8%, 9.8%, 15%, 15%, 15%.

### Timeline

- 5 August 2021: Published
- 27 March 2024: Record last updated

### How Precursor Intelligence ranks it

CVE-2021-22926 scores **53 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-2021-22926?

The published record lists 26 products. Versions are as published: "7.33.0 to before 7.78.0" means from 7.33.0 up to, but not including, 7.78.0.

- [Curl](https://www.precursorintelligence.com/product/haxx/curl) by [Haxx](https://www.precursorintelligence.com/vendors/haxx) (Application): 7.33.0 to before 7.78.0
- [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 5.7.35, 8.0.0 to 8.0.26
- [Active Iq Unified Manager](https://www.precursorintelligence.com/product/netapp/active_iq_unified_manager) 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
- [H300e](https://www.precursorintelligence.com/product/netapp/h300e) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H300e Firmware](https://www.precursorintelligence.com/product/netapp/h300e_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H300s](https://www.precursorintelligence.com/product/netapp/h300s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H300s Firmware](https://www.precursorintelligence.com/product/netapp/h300s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H410s](https://www.precursorintelligence.com/product/netapp/h410s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H410s Firmware](https://www.precursorintelligence.com/product/netapp/h410s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H500e](https://www.precursorintelligence.com/product/netapp/h500e) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H500e Firmware](https://www.precursorintelligence.com/product/netapp/h500e_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H500s](https://www.precursorintelligence.com/product/netapp/h500s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H500s Firmware](https://www.precursorintelligence.com/product/netapp/h500s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H700e](https://www.precursorintelligence.com/product/netapp/h700e) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H700e Firmware](https://www.precursorintelligence.com/product/netapp/h700e_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [H700s](https://www.precursorintelligence.com/product/netapp/h700s) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Hardware): version not specified
- [H700s Firmware](https://www.precursorintelligence.com/product/netapp/h700s_firmware) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Operating system): version not specified
- [Hci Management Node](https://www.precursorintelligence.com/product/netapp/hci_management_node) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Oncommand Insight](https://www.precursorintelligence.com/product/netapp/oncommand_insight) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Oncommand Workflow Automation](https://www.precursorintelligence.com/product/netapp/oncommand_workflow_automation) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [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
- [Snapcenter](https://www.precursorintelligence.com/product/netapp/snapcenter) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified
- [Solidfire](https://www.precursorintelligence.com/product/netapp/solidfire) by [Netapp](https://www.precursorintelligence.com/vendors/netapp) (Application): version not specified

## How do I fix CVE-2021-22926?

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)
- [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)
- [hackerone.com](https://hackerone.com/reports/1234760) (Exploit, 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)
- [security.gentoo.org](https://security.gentoo.org/glsa/202212-01) (Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20210902-0003/) (Third-party advisory)
- [security.netapp.com](https://security.netapp.com/advisory/ntap-20211022-0003/) (Third-party advisory)

## Questions

### What is CVE-2021-22926?

CVE-2021-22926 is a high-severity flaw in Curl 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 take it offline.

### How serious is CVE-2021-22926?

It scores 7.5 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-22926 is 53 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.

### Is CVE-2021-22926 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 15%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2021-22926 affect?

For Curl from Haxx: 7.33.0 to before 7.78.0. The record lists 26 products in all, each with its versions, under "Who is affected" on this page.

### How do I fix CVE-2021-22926?

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-2021-22926 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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