How severe is CVE-2023-27533?

CVE-2023-27533 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2023-27533 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-27533?

CVE-2023-27533 primarily affects Haxx Curl. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-27533?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2023-27533 published?

CVE-2023-27533 was published on 2023-03-30 and last updated on 2026-06-17.

CVE-2023-27533

CVE-2023-27533 is a high-severity vulnerability in Haxx Curl with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-74.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-74
Affected product: Haxx Curl
Published: 2023-03-30
Last modified: 2026-06-17

Description

A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.

Frequently asked questions

What is CVE-2023-27533?: A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.
How severe is CVE-2023-27533?: CVE-2023-27533 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2023-27533 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-27533?: CVE-2023-27533 primarily affects Haxx Curl. In total, 10 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-27533?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2023-27533 published?: CVE-2023-27533 was published on 2023-03-30 and last updated on 2026-06-17.

References

Affected products (10)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*
cpe:2.3:a:netapp:clustered_data_ontap:9.0:-:*:*:*:*:*:*
cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*
cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:*
cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:*

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