CVE catalog
CVE-2021-22947
curl: CVE-2021-22947
- Severity
- Medium · CVSS 6.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 3.01% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | curl | sid | 8.23.0-1 | fixed |
| Debian | curl | forky | 8.22.0-1 | fixed |
| Debian | curl | trixie | 8.14.1-2+deb13u5 | fixed |
| Debian | curl | trixie-security | 8.14.1-2+deb13u7 | fixed |
| Debian | curl | bookworm | 7.88.1-10+deb12u15 | fixed |
| Debian | curl | bookworm-security | 7.88.1-10+deb12u5 | fixed |
| Cpe | curl | Not reported | 7.79.0 | fixed |
| Cpe | fedora | Not reported | Not reported | unknown |
| Cpe | debian_linux | Not reported | Not reported | unknown |
| Cpe | cloud_backup | Not reported | Not reported | unknown |
| Cpe | clustered_data_ontap | Not reported | Not reported | unknown |
| Cpe | h300s_firmware | Not reported | Not reported | unknown |
| Cpe | h500s_firmware | Not reported | Not reported | unknown |
| Cpe | h700s_firmware | Not reported | Not reported | unknown |
| Cpe | h300e_firmware | Not reported | Not reported | unknown |
| Cpe | h500e_firmware | Not reported | Not reported | unknown |
| Cpe | h700e_firmware | Not reported | Not reported | unknown |
| Cpe | h410s_firmware | Not reported | Not reported | unknown |
| Cpe | solidfire_baseboard_management_controller_firmware | Not reported | Not reported | unknown |
| Cpe | communications_cloud_native_core_binding_support_function | Not reported | Not reported | unknown |
| Cpe | communications_cloud_native_core_network_function_cloud_native_environment | Not reported | Not reported | unknown |
| Cpe | communications_cloud_native_core_network_repository_function | Not reported | Not reported | unknown |
| Alpine | curl | 3.11 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.12 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.13 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.14 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.15 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.16 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.17 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.18 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.19 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.20 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.21 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.22 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.23 | 7.79.0-r0 | fixed |
| Alpine | curl | 3.24 | 7.79.0-r0 | fixed |
| Ubuntu | curl | pro | 7.43.0-1ubuntu2 | vulnerable |
| Ubuntu | curl | pro | 7.45.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | pro | 7.46.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.1 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.2 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.3 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.4 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.5 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.6 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.7 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.8 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.9 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.11 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.12 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.13 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.14 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.15 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.16 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.18 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.19 | vulnerable |
| Ubuntu | curl | pro | 7.47.0-1ubuntu2.19+esm1 | fixed |
| Ubuntu | curl | 18.04 | 7.55.1-1ubuntu2 | vulnerable |
| Ubuntu | curl | 18.04 | 7.55.1-1ubuntu2.1 | vulnerable |
| Ubuntu | curl | 18.04 | 7.57.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu1 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu2 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.1 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.2 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.3 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.5 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.6 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.7 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.8 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.9 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.10 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.12 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.13 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.14 | vulnerable |
| Ubuntu | curl | 18.04 | 7.58.0-2ubuntu3.15 | fixed |
| Ubuntu | curl | 20.04 | 7.65.3-1ubuntu3 | vulnerable |
| Ubuntu | curl | 20.04 | 7.65.3-1ubuntu4 | vulnerable |
| Ubuntu | curl | 20.04 | 7.66.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | 20.04 | 7.67.0-2ubuntu1 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu1 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.1 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.2 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.4 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.5 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.6 | vulnerable |
| Ubuntu | curl | 20.04 | 7.68.0-1ubuntu2.7 | fixed |
| Ubuntu | curl | 22.04 | 7.74.0-1.3ubuntu2 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | curl | source | sid | 7.79.1-1 | not yet assigned | Not reported | Not reported |
| Debian | curl | source | forky | 7.79.1-1 | not yet assigned | Not reported | Not reported |
| Debian | curl | source | trixie | 7.79.1-1 | not yet assigned | Not reported | Not reported |
| Debian | curl | source | bookworm | 7.79.1-1 | not yet assigned | Not reported | Not reported |
| Cpe | curl | cpe | Not reported | 7.79.0 | Not reported | NVD-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.11 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.12 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.13 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.14 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.15 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.16 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.17 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.18 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.19 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.20 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.21 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.22 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.23 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Alpine | curl | apk | 3.24 | 7.79.0-r0 | Not reported | ALPINE-CVE-2021-22947 | Not reported |
| Ubuntu | curl | deb | pro | 7.47.0-1ubuntu2.19+esm1 | Not reported | UBUNTU-CVE-2021-22947 | Not reported |
| Ubuntu | curl | deb | 18.04 | 7.58.0-2ubuntu3.15 | Not reported | UBUNTU-CVE-2021-22947 | Not reported |
| Ubuntu | curl | deb | 20.04 | 7.68.0-1ubuntu2.7 | Not reported | UBUNTU-CVE-2021-22947 | Not reported |
| Ubuntu | curl | deb | 22.04 | 7.74.0-1.3ubuntu2 | Not reported | UBUNTU-CVE-2021-22947 | Not reported |
OpenFactory catalog packages
Matching against OpenFactory catalog package versions is in progress.
[Debian 12 (Bookworm)]
- [curl]Unknown
Details (6)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· amd64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· arm64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl3-gnutls]Unknown
Source package: [curl]
Details (6)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· amd64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· arm64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl3-nss]Unknown
Source package: [curl]
Details (4)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl4]Unknown
Source package: [curl]
Details (6)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· amd64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· arm64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl4-doc]Unknown
Source package: [curl]
Details (6)
7.88.1-10+deb12u15· all · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· all · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· all · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· all · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· all · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· all · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl4-gnutls-dev]Unknown
Source package: [curl]
Details (6)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· amd64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· arm64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl4-nss-dev]Unknown
Source package: [curl]
Details (4)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
- [libcurl4-openssl-dev]Unknown
Source package: [curl]
Details (6)
7.88.1-10+deb12u15· amd64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u15· arm64 · bookwormFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· amd64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
8.14.1-2+deb13u2~bpo13+1· arm64 · bookworm-backportsFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· amd64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
7.88.1-10+deb12u5· arm64 · bookworm-securityFixed · Fixed:
7.79.1-1dsa · curl · debian · bookworm
Observed:
References
- [https://cert-portal.siemens.com/productcert/csaf/ssa-389290.json]
- [https://ftp.suse.com/pub/projects/security/csaf/rhsa-2021_4059.json]
- [https://nvd.nist.gov/vuln/detail/CVE-2021-22947]
- [https://osv.dev/vulnerability/ALPINE-CVE-2021-22947]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2021-22947]
- [https://security-tracker.debian.org/tracker/CVE-2021-22947]
- [https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-22947.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2023/wid-sec-w-2023-1350.json]
[CERT-Bund public advisories] · [CISA cybersecurity advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]