CVE-2026-5773: Haxx Curl server-side request forgery (SSRF) (CVSS 7.5)

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Affected products

Haxx Curl≥ 7.40.0 < 8.20.0

Remediation

Fixed in

Haxx Curl≥ 8.20.0

Patch & vendor advisories

References

https://curl.se/docs/CVE-2026-5773.htmlPatchVendor Advisory
https://curl.se/docs/CVE-2026-5773.jsonVendor Advisory
https://hackerone.com/reports/3650689ExploitIssue TrackingThird Party Advisory
http://www.openwall.com/lists/oss-security/2026/04/29/9Mailing ListPatchThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-5773 being actively exploited?

CVE-2026-5773 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.66%.

How severe is CVE-2026-5773?

CVE-2026-5773 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.66% probability of exploitation.

Which products are affected by CVE-2026-5773?

Affected products include Haxx Curl.

How do I fix CVE-2026-5773?

Upgrade affected software to a fixed version, for example Haxx Curl 8.20.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-5773 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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