CVE-2026-92389

High

Description

libcurl's TFTP state machine fails to validate state transitions against the requested transfer direction, accepting opening server responses for both reads and writes interchangeably. A malicious TFTP server can respond to a download request in a way that forces the client into transmit mode, prompting libcurl to consume and transmit data from the handle's persistent `CURLOPT_READDATA` pointer - including data remaining from unrelated prior operations, such as an HTTP POST request executed on a reused handle.

SeverityHigh
CVSS8.1
Exploit probability—
ProductCurl
PublishedOct 20, 2026
First seenOct 20, 2026

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
curl curl8.22.0, 8.21.0, 8.20.0, 8.19.0, 8.18.0, 8.17.0, 8.16.0, 8.15.0, 8.14.1, 8.14.0, 8.13.0, 8.12.1, 8.12.0, 8.11.1, 8.11.0, 8.10.1, 8.10.0, 8.9.1, 8.9.0, 8.8.0, 8.7.1, 8.7.0, 8.6.0, 8.5.0, 8.4.0, 8.3.0, 8.2.1, 8.2.0, 8.1.2, 8.1.1, 8.1.0, 8.0.1, 8.0.0, 7.88.1, 7.88.0, 7.87.0, 7.86.0, 7.85.0, 7.84.0, 7.83.1, 7.83.0, 7.82.0, 7.81.0, 7.80.0, 7.79.1, 7.79.0, 7.78.0, 7.77.0, 7.76.1, 7.76.0, 7.75.0, 7.74.0, 7.73.0, 7.72.0, 7.71.1, 7.71.0, 7.70.0, 7.69.1, 7.69.0, 7.68.0, 7.67.0, 7.66.0, 7.65.3, 7.65.2, 7.65.1, 7.65.0, 7.64.1, 7.64.0, 7.63.0, 7.62.0, 7.61.1, 7.61.0, 7.60.0, 7.59.0, 7.58.0, 7.57.0, 7.56.1, 7.56.0, 7.55.1, 7.55.0, 7.54.1, 7.54.0, 7.53.1, 7.53.0, 7.52.1, 7.52.0, 7.51.0, 7.50.3, 7.50.2, 7.50.1, 7.50.0, 7.49.1, 7.49.0, 7.48.0, 7.47.1, 7.47.0, 7.46.0, 7.45.0, 7.44.0, 7.43.0, 7.42.1, 7.42.0, 7.41.0, 7.40.0, 7.39.0, 7.38.0, 7.37.1, 7.37.0, 7.36.0, 7.35.0, 7.34.0, 7.33.0, 7.32.0, 7.31.0, 7.30.0, 7.29.0, 7.28.1, 7.28.0, 7.27.0, 7.26.0, 7.25.0, 7.24.0, 7.23.1, 7.23.0, 7.22.0, 7.21.7, 7.21.6, 7.21.5, 7.21.4, 7.21.3, 7.21.2, 7.21.1, 7.21.0, 7.20.1, 7.20.0, 7.19.7, 7.19.6, 7.19.5, 7.19.4, 7.19.3, 7.19.2, 7.19.1, 7.19.0, 7.18.2, 7.18.1, 7.18.0, 7.17.1, 7.17.0, 7.16.4, 7.16.3, 7.16.2, 7.16.1, 7.16.0, 7.15.5, 7.15.4, 7.15.3, 7.15.2, 7.15.1, 7.15.0—

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