CVE-2026-5773

Name: CVE-2026-5773
Creator: NVD / NIST
Published: 2026-05-13T13:01:56.307+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.55%

Last modified Jun 17, 2026

CVE-2026-5773 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different 'share' than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. EPSS estimates a 0.55% chance of exploitation in the next 30 days.

Description

libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead. When reusing a connection a range of criteria must be met. Due to a logical error in the code, a network transfer operation that was requested by an application could wrongfully reuse an existing SMB connection to the same server that was using a different 'share' than the new subsequent transfer should. This could in unlucky situations lead to the download of the wrong file or the upload of a file to the wrong place. When this happens, the same credentials are used and the server name is the same.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

0.55%

41.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-918

Affected Software

Vendor	Product	Versions
Haxx	Curl	>= 7.40.0, < 8.20.0

References

https://curl.se/docs/CVE-2026-5773.htmlPatch, Vendor Advisory
https://curl.se/docs/CVE-2026-5773.jsonVendor Advisory
https://hackerone.com/reports/3650689Exploit, Issue Tracking, Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/04/29/9Mailing List, Patch, Third Party Advisory
https://hackerone.com/reports/3650689Exploit, Issue Tracking, Third Party Advisory

Timeline

Published: May 13, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-5773?

How severe is CVE-2026-5773?

CVE-2026-5773 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.55% probability of exploitation in the next 30 days.

How do I fix CVE-2026-5773?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-5773?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST