CVE-2021-22947

5.9 MEDIUM
Published: September 29, 2021 Modified: April 16, 2026
View on NVD

Description

When curl >= 7.20.0 and <= 7.78.0 connects to an IMAP or POP3 server to retrieve data using STARTTLS to upgrade to TLS security, the server can respond and send back multiple responses at once that curl caches. curl would then upgrade to TLS but not flush the in-queue of cached responses but instead continue using and trustingthe responses it got *before* the TLS handshake as if they were authenticated.Using this flaw, it allows a Man-In-The-Middle attacker to first inject the fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attacker's injected data comes from the TLS-protected server.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
http://seclists.org/fulldisclosure/2022/Mar/29
Source: support@hackerone.com
Mailing List Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
Source: support@hackerone.com
Patch Third Party Advisory
https://hackerone.com/reports/1334763
Source: support@hackerone.com
Exploit Issue Tracking Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/09/msg00022.html
Source: support@hackerone.com
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html
Source: support@hackerone.com
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202212-01
Source: support@hackerone.com
Third Party Advisory
https://security.netapp.com/advisory/ntap-20211029-0003/
Source: support@hackerone.com
Third Party Advisory
https://support.apple.com/kb/HT213183
Source: support@hackerone.com
Release Notes Third Party Advisory
https://www.debian.org/security/2022/dsa-5197
Source: support@hackerone.com
Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html
Source: support@hackerone.com
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: support@hackerone.com
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html
Source: support@hackerone.com
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: support@hackerone.com
Patch Third Party Advisory
http://seclists.org/fulldisclosure/2022/Mar/29
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://hackerone.com/reports/1334763
Source: af854a3a-2127-422b-91ae-364da2661108
Exploit Issue Tracking Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/09/msg00022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/08/msg00017.html
Source: af854a3a-2127-422b-91ae-364da2661108
Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202212-01
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://security.netapp.com/advisory/ntap-20211029-0003/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://support.apple.com/kb/HT213183
Source: af854a3a-2127-422b-91ae-364da2661108
Release Notes Third Party Advisory
https://www.debian.org/security/2022/dsa-5197
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpujul2022.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html
Source: af854a3a-2127-422b-91ae-364da2661108
Patch Third Party Advisory

30 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.9 / 10.0
EPSS (Exploit Probability)
0.3%
49th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

fedoraproject debian apple netapp siemens splunk haxx oracle