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Vulnerability record · CVE-2021-22876 · published 1 April 2021

CVE-2021-22876: Haxx libcurl information exposure vulnerability

Haxx · Libcurl

curl 7.1.1 to and including 7.75.0 is vulnerable to an "Exposure of Private Personal Information to an Unauthorized Actor" by leaking credentials in the HTTP Referer: header. libcurl does not strip off user credentials from the URL when automatically populating the Referer: HTTP request header field in outgoing HTTP requests, and therefore risks leaking sensitive data to the server that is the target of the second HTTP request.

5.3 CVSS 3.1 Medium EPSS 5.3% · top 7.3% CWE-359 · CWE-359CWE-200 · Information exposure
5.3CVSS 3.1 base score, v2 5.0
5.3%EPSS exploitation probability, 30 days
NoNot in CISA KEV
12Affected product versions listed by NVD
22References, 2 tagged exploit
14 Oct 2026Last modified by NVD

Description

curl 7.1.1 to and including 7.75.0 is vulnerable to an "Exposure of Private Personal Information to an Unauthorized Actor" by leaking credentials in the HTTP Referer: header. libcurl does not strip off user credentials from the URL when automatically populating the Referer: HTTP request header field in outgoing HTTP requests, and therefore risks leaking sensitive data to the server that is the target of the second HTTP request.

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

Affected products

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

References

LinkTags
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://curl.se/docs/CVE-2021-22876.html PatchVendor Advisory
https://hackerone.com/reports/1101882 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00019.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2 Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYS Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6 Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202105-36 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210521-0007/ Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf PatchThird Party Advisory
https://curl.se/docs/CVE-2021-22876.html PatchVendor Advisory
https://hackerone.com/reports/1101882 ExploitIssue TrackingPatchThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/05/msg00019.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2 Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYS Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6 Mailing ListThird Party Advisory
https://security.gentoo.org/glsa/202105-36 Third Party Advisory
https://security.netapp.com/advisory/ntap-20210521-0007/ Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Third Party Advisory
https://cert-portal.siemens.com/productcert/html/ssa-389290.html
https://cert-portal.siemens.com/productcert/html/ssa-398330.html

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Source: NIST National Vulnerability Database (record CVE-2021-22876), CISA KEV, FIRST EPSS (scores of 2026-11-13). This page is refreshed as NVD updates the record.