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MEDIUM

CVE-2021-22876

CVSS v3

5.3

MEDIUM

EPSS Score

5.3 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libcurlAlmaLinux:8all versions · fixed in 7.61.1-22.el8and 3 other packages

Vendor advisories

  • CVE-2021-22876 Red Hat Product Security204 products fixed · 17 known affected

    curl: Leak of authentication credentials in URL via automatic Referer

    rh-dotnet21-curl.src as a component of .NET Core 2.1 on Red Hat Enterprise Linux · rh-dotnet21-libcurl as a component of .NET Core 2.1 on Red Hat Enterprise Linux · rh-dotnet21-libcurl-devel as a component of .NET Core 2.1 on Red Hat Enterprise Linux

  • ICSA-23-348-10 CISA5 known affected

    Siemens SIMATIC S7-1500

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0)

  • SSA-398330 Siemens ProductCERT5 known affected

    SSA-398330: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP >= V3.1.0 and < V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.0 < V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.0 < V3.1.5

  • RHSA-2022:1354 Red Hat Product Security15 products fixed

    Red Hat Security Advisory: rh-dotnet31-curl security update

  • ICSA-22-069-09 CISA1 known affected

    Siemens SINEC INS

    SINEC INS

  • SSA-389290 Siemens ProductCERT1 known affected

    SSA-389290: Third-Party Component Vulnerabilities in SINEC INS

    SINEC INS

3 more advisories

Full record on 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.

Technical details

Published
2021-04-01

Frequently asked questions

What is CVE-2021-22876?

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.

Is CVE-2021-22876 actively exploited?

Active exploitation of CVE-2021-22876 has not been confirmed. Its EPSS score was 5.3% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-22876?

CVE-2021-22876 has a CVSS v3 base score of 5.3 (MEDIUM severity).

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