---
id: CVE-2021-22890
title: >-
  curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a
  malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3
  session tickets
summary: >-
  curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a
  malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3
  session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse
  session tickets…
severity: low
cvss: 3.7
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'
cwe:
  - CWE-300
  - CWE-290
vendor: haxx
product: libcurl
affected:
  - 'libcurl >= 7.63.0, <= 7.75.0'
  - fedora = 32
  - fedora = 33
  - fedora = 34
  - hci_management_node
  - solidfire
  - hci_storage_node
  - fabric_operating_system
  - debian_linux = 9.0
  - sinec_infrastructure_network_services < 1.0.1.1
  - communications_billing_and_revenue_management = 12.0.0.3.0
  - essbase = 21.2
  - 'universal_forwarder >= 8.2.0, < 8.2.12'
  - 'universal_forwarder >= 9.0.0, < 9.0.6'
  - universal_forwarder = 9.1.0
patched:
  - sinec_infrastructure_network_services 1.0.1.1
  - universal_forwarder 9.0.6
published: '2021-04-01'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T11:16:52.373'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-22890'
references:
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf'
    label: support@hackerone.com
  - url: 'https://curl.se/docs/CVE-2021-22890.html'
    label: support@hackerone.com
  - url: 'https://hackerone.com/reports/1129529'
    label: support@hackerone.com
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
    label: support@hackerone.com
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
    label: support@hackerone.com
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
    label: support@hackerone.com
  - url: 'https://security.gentoo.org/glsa/202105-36'
    label: support@hackerone.com
  - url: 'https://security.netapp.com/advisory/ntap-20210521-0007/'
    label: support@hackerone.com
  - url: 'https://www.oracle.com//security-alerts/cpujul2021.html'
    label: support@hackerone.com
  - url: 'https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://curl.se/docs/CVE-2021-22890.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://hackerone.com/reports/1129529'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2ZC5BMIOKLBQJSFCHEDN2G2C2SH274BP/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ITVWPVGLFISU5BJC2BXBRYSDXTXE2YGC/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KQUIOYX2KUU6FIUZVB5WWZ6JHSSYSQWJ/
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.gentoo.org/glsa/202105-36'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://security.netapp.com/advisory/ntap-20210521-0007/'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://www.oracle.com//security-alerts/cpujul2021.html'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-389290.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-398330.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
epss: 0.02978
epssPercentile: 0.86938
ingestedAt: '2026-10-14T11:27:22.122Z'
---

## Overview

curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.

## Affected

- `libcurl >= 7.63.0, <= 7.75.0`
- `fedora = 32`
- `fedora = 33`
- `fedora = 34`
- `hci_management_node`
- `solidfire`
- `hci_storage_node`
- `fabric_operating_system`
- `debian_linux = 9.0`
- `sinec_infrastructure_network_services < 1.0.1.1`
- `communications_billing_and_revenue_management = 12.0.0.3.0`
- `essbase = 21.2`
- `universal_forwarder >= 8.2.0, < 8.2.12`
- `universal_forwarder >= 9.0.0, < 9.0.6`
- `universal_forwarder = 9.1.0`

## Remediation

Upgrade past the affected range:

- `sinec_infrastructure_network_services 1.0.1.1`
- `universal_forwarder 9.0.6`