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Vulnerability record · CVE-2021-22925 · published 5 August 2021

CVE-2021-22925: Haxx curl information exposure vulnerability

Haxx · Curl

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl. This rarely used option is used to send variable=content pairs toTELNET servers.Due to flaw in the option parser for sending `NEW_ENV` variables, libcurlcould be made to pass on uninitialized data from a stack based buffer to theserver. Therefore potentially revealing sensitive internal information to theserver using a clear-text network protocol.This could happen because curl did not call and use sscanf() correctly whenparsing the string provided by the application.

5.3 CVSS 3.1 Medium EPSS 4.9% · top 8.1% CWE-200 · Information exposureCWE-908 · Use of uninitialized resource
5.3CVSS 3.1 base score, v2 5.0
4.9%EPSS exploitation probability, 30 days
NoNot in CISA KEV
20Affected product versions listed by NVD
24References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

curl supports the `-t` command line option, known as `CURLOPT_TELNETOPTIONS`in libcurl. This rarely used option is used to send variable=content pairs toTELNET servers.Due to flaw in the option parser for sending `NEW_ENV` variables, libcurlcould be made to pass on uninitialized data from a stack based buffer to theserver. Therefore potentially revealing sensitive internal information to theserver using a clear-text network protocol.This could happen because curl did not call and use sscanf() correctly whenparsing the string provided by the application.

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

Affected products

20 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://seclists.org/fulldisclosure/2021/Sep/39 Mailing ListThird Party Advisory
http://seclists.org/fulldisclosure/2021/Sep/40 Mailing ListThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf Third Party Advisory
https://hackerone.com/reports/1223882 ExploitIssue TrackingPatchThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4 Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202212-01 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210902-0003/ Third Party Advisory
https://support.apple.com/kb/HT212804 Third Party Advisory
https://support.apple.com/kb/HT212805 Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory
http://seclists.org/fulldisclosure/2021/Sep/39 Mailing ListThird Party Advisory
http://seclists.org/fulldisclosure/2021/Sep/40 Mailing ListThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-484086.pdf Third Party Advisory
https://hackerone.com/reports/1223882 ExploitIssue TrackingPatchThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FRUCW2UVNYUDZF72DQLFQR4 Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202212-01 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210902-0003/ Third Party Advisory
https://support.apple.com/kb/HT212804 Third Party Advisory
https://support.apple.com/kb/HT212805 Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html PatchThird Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html PatchThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2021-22925), CISA KEV, FIRST EPSS (scores of 2026-10-07). This page is refreshed as NVD updates the record.