Skip to content
Fencer Vulns
high 7.5

CVE-2021-22946 json

A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-re…

published 2021-09-29 5 y ago modified 2026-10-14 26 d ago also EUVD-2021-10074 , JLSEC-2026-1339

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.5%
EPSS 4.5% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

A user can tell curl >= 7.20.0 and <= 7.78.0 to require a successful upgrade to TLS when speaking to an IMAP, POP3 or FTP server (`--ssl-reqd` on the command line or`CURLOPT_USE_SSL` set to `CURLUSESSL_CONTROL` or `CURLUSESSL_ALL` withlibcurl). This requirement could be bypassed if the server would return a properly crafted but perfectly legitimate response.This flaw would then make curl silently continue its operations **withoutTLS** contrary to the instructions and expectations, exposing possibly sensitive data in clear text over the network.

Patch / fix

  • julia LibCURL_jll 7.81.0+0
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.5
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.5
  • curl Debian 14, Debian 13, Debian 12 7.79.1-1

debian advisories DEBIAN-CVE-2021-22946

  • curl Ubuntu 18.04 LTS 7.58.0-2ubuntu3.15
  • curl Ubuntu 20.04 LTS 7.68.0-1ubuntu2.7
  • curl Ubuntu 22.04 LTS 7.74.0-1.3ubuntu2
  • curl Ubuntu Pro 14.04 LTS 7.35.0-1ubuntu2.20+esm8
  • curl Ubuntu Pro 16.04 LTS 7.47.0-1ubuntu2.19+esm1

ubuntu advisories UBUNTU-CVE-2021-22946

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rh-dotnet31-curl RHEL 3.1 DOTNET 7.61.1-22.el7_9
  • rh-dotnet31-libcurl RHEL 3.1 DOTNET 7.61.1-22.el7_9
  • curl RHEL 8 7.61.1-18.el8_4.2
  • libcurl RHEL 8 7.61.1-18.el8_4.2
  • libcurl-minimal RHEL 8 7.61.1-18.el8_4.2
  • curl RHEL 8.2 EUS 7.61.1-12.el8_2.4
  • libcurl RHEL 8.2 EUS 7.61.1-12.el8_2.4
  • libcurl-minimal RHEL 8.2 EUS 7.61.1-12.el8_2.4

red hat advisories RHSA-2022:1354RHSA-2022:0635RHSA-2021:4059

  • curl SLES for SAP 12 SP4, SLES 12 SP4-LTSS, OpenStack Cloud Crowbar 9 +1 more 7.60.0-4.30.1
  • curl SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 7.60.0-11.28.1
  • curl SLE Module for Basesystem 15 SP3, SLE Module for Basesystem 15 SP2, SLE Micro 5.1 +1 more 7.66.0-4.27.1
  • curl SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 7.60.0-25.1
  • curl-openssl1 SLES 11-SECURITY 7.37.0-70.74.1

suse advisories SUSE-SU-2021:3351-1SUSE-SU-2021:3332-1SUSE-SU-2021:3298-1SUSE-SU-2021:3297-1SUSE-SU-2021:14807-1

  • curl openSUSE Tumbleweed 7.79.1-1.1
  • curl openSUSE Leap 15.2 7.66.0-lp152.3.24.1
  • curl-mini openSUSE Leap 15.2 7.66.0-lp152.3.24.1
  • curl openSUSE Leap 15.3 7.66.0-4.27.1

opensuse advisories openSUSE-SU-2024:10582-1openSUSE-SU-2021:1384-1openSUSE-SU-2021:3298-1

  • curl Rocky Linux 8 7.61.1-18.el8_4.2

rocky linux advisories RLSA-2021:4059

  • curl Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 7.79.0-r0

alpine advisories ALPINE-CVE-2021-22946

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • curl CBL-Mariner 2.0 7.82.0-1

azure linux advisories AZL-6365

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • curl Arch Linux 7.79.0-1
  • lib32-curl Arch Linux 7.79.0-1
  • libcurl-compat Arch Linux 7.79.0-1
  • lib32-libcurl-compat Arch Linux 7.79.0-1
  • libcurl-gnutls Arch Linux 7.79.0-1
  • lib32-libcurl-gnutls Arch Linux 7.79.0-1

arch linux advisories AVG-2384AVG-2385AVG-2386AVG-2387AVG-2388AVG-2389

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-22946 updated cvss 7.5

curl: Requirement to use TLS not properly enforced for IMAP, POP3, and FTP protocols

  • Red Hat .NET Core 2.1 on Red Hat Enterprise Linux rh-dotnet21-curl, rh-dotnet21-libcurl Red Hat Ceph Storage 2 curl, libcurl
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 curl, libcurl Red Hat Software Collections httpd24-curl, httpd24-libcurl
    affected: no fix available
  • Red Hat .NET Core on Red Hat Enterprise Linux ComputeNode (v. 7) rh-dotnet31-curl 7.61.1-22.el7_9, rh-dotnet31-libcurl 7.61.1-22.el7_9 Red Hat .NET Core on Red Hat Enterprise Linux Server (v. 7) rh-dotnet31-curl 7.61.1-22.el7_9, rh-dotnet31-libcurl 7.61.1-22.el7_9 Red Hat .NET Core on Red Hat Enterprise Linux Workstation (v. 7) rh-dotnet31-curl 7.61.1-22.el7_9, rh-dotnet31-libcurl 7.61.1-22.el7_9
    fixed: vendor fix RHSA-2022:1354
  • Red Hat Enterprise Linux BaseOS (v. 8) curl 7.61.1-18.el8_4.2, libcurl 7.61.1-18.el8_4.2, libcurl-minimal 7.61.1-18.el8_4.2
    fixed: vendor fix RHSA-2021:4059
  • Red Hat Enterprise Linux BaseOS EUS (v. 8.2) curl 7.61.1-12.el8_2.4, libcurl 7.61.1-12.el8_2.4, libcurl-minimal 7.61.1-12.el8_2.4
    fixed: vendor fix RHSA-2022:0635
  • Red Hat Enterprise Linux 6 curl, libcurl Red Hat Enterprise Linux 9 curl, libcurl, curl-minimal, libcurl-minimal Red Hat JBoss Core Services jbcs-httpd24-curl jbcs-httpd24-curl
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-23-348-10 updated cvss 7.5

Siemens SIMATIC S7-1500

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.0, < 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.0, < 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.0, < 3.1.5
    affected: fixed in V3.1.5, mitigation support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-23-194-01 updated cvss 7.5

Siemens RUGGEDCOM ROX

  • Siemens RUGGEDCOM ROX MX5000 <V2.16.0 Siemens RUGGEDCOM ROX MX5000RE <V2.16.0 Siemens RUGGEDCOM ROX RX1400 <V2.16.0 Siemens RUGGEDCOM ROX RX1500 <V2.16.0 Siemens RUGGEDCOM ROX RX1501 <V2.16.0 Siemens RUGGEDCOM ROX RX1510 <V2.16.0
    +5 more products
    Siemens RUGGEDCOM ROX RX1511 <V2.16.0 Siemens RUGGEDCOM ROX RX1512 <V2.16.0 Siemens RUGGEDCOM ROX RX1524 <V2.16.0 Siemens RUGGEDCOM ROX RX1536 <V2.16.0 Siemens RUGGEDCOM ROX RX5000 <V2.16.0
    affected: fixed in V2.16.0 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

4.54% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/1334111 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected packages

ecosystem package affected fixed in
julia LibCURL_jll
<7.81.0+0
7.81.0+0

Affected products

  • n/a https://github.com/curl/curl
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-325 Missing Cryptographic Step
  • CWE-319 Cleartext Transmission of Sensitive Information
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.