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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | https://github.com/curl/curl | curl 7.20.0 to and including 7.78.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | curl | 7.79.1-1 | — |
| Debian 13 | curl | 7.79.1-1 | — |
| Debian 12 | curl | 7.79.1-1 | — |
| Debian 11 | curl | 7.74.0-1.3+deb11u2 | DSA-5197-1 |
| Debian 10 | curl | 7.64.0-4+deb10u3 | DLA-3085-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 9 | curl | 7.52.1-5+deb9u16 | DLA-2773-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 22.04 LTS | curl | 7.74.0-1.3ubuntu2 | — |
| Ubuntu 20.04 LTS | curl | 7.68.0-1ubuntu2.7 | USN-5079-1 |
| Ubuntu 18.04 LTS | curl | 7.58.0-2ubuntu3.15 | USN-5079-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 16.04 LTS | curl | 7.47.0-1ubuntu2.19+esm1 | USN-5079-2 |
| Ubuntu Pro 14.04 LTS | curl | 7.35.0-1ubuntu2.20+esm8 | USN-5079-2 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | curl +3 | 7.61.1-18.el8_4.2 | RHSA-2021:4059 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhel Dotnet 3 | rh-dotnet31-curl +2 | 7.61.1-22.el7_9 | RHSA-2022:1354 |
| RHEL 8.2 EUS | curl +3 | 7.61.1-12.el8_2.4 | RHSA-2022:0635 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | curl | 7.61.1-18.el8_4.2 | RLSA-2021:4059 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | curl | 7.66.0-4.27.1 | SUSE-SU-2021:3298-1 |
| SLES 15 SP2 | curl | 7.66.0-4.27.1 | SUSE-SU-2021:3298-1 |
| SLES 15 SP1 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SLES 15 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SLES 12 SP5 | curl | 7.60.0-11.28.1 | SUSE-SU-2021:3332-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | curl | 7.60.0-4.30.1 | SUSE-SU-2021:3351-1 |
| SLES 11 | curl-openssl1 | 7.37.0-70.74.1 | SUSE-SU-2021:14807-1 |
| SLES for SAP 15 SP1 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SLES for SAP 15 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SLES for SAP 12 SP5 | curl | 7.60.0-11.28.1 | SUSE-SU-2021:3332-1 |
| SLES for SAP 12 SP4 | curl | 7.60.0-4.30.1 | SUSE-SU-2021:3351-1 |
| SLE Micro 5.1 | curl | 7.66.0-4.27.1 | SUSE-SU-2021:3298-1 |
| SLE Micro 5.0 | curl | 7.66.0-4.27.1 | SUSE-SU-2021:3298-1 |
| SLE HPC 15 SP1 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SLE HPC 15 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
| SUSE OpenStack Cloud Crowbar 9 | curl | 7.60.0-4.30.1 | SUSE-SU-2021:3351-1 |
| SUSE OpenStack Cloud 9 | curl | 7.60.0-4.30.1 | SUSE-SU-2021:3351-1 |
| SUSE Enterprise Storage 6 | curl | 7.60.0-25.1 | SUSE-SU-2021:3297-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | curl | 7.79.1-1.1 | openSUSE-SU-2024:10582-1 |
| openSUSE Leap 15.3 | curl | 7.66.0-4.27.1 | openSUSE-SU-2021:3298-1 |
| openSUSE Leap 15.2 | curl +1 | 7.66.0-lp152.3.24.1 | openSUSE-SU-2021:1384-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 7.79.0-r0 | — |
| Alpine v3.23 | curl | 7.79.0-r0 | — |
| Alpine v3.22 | curl | 7.79.0-r0 | — |
| Alpine v3.21 | curl | 7.79.0-r0 | — |
| Alpine v3.20 | curl | 7.79.0-r0 | — |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | curl | 7.79.0-r0 | — |
| Alpine v3.18 | curl | 7.79.0-r0 | — |
| Alpine v3.17 | curl | 7.79.0-r0 | — |
| Alpine v3.16 | curl | 7.79.0-r0 | — |
| Alpine v3.15 | curl | 7.79.0-r0 | — |
| Alpine v3.14 | curl | 7.79.0-r0 | — |
| Alpine v3.13 | curl | 7.79.0-r0 | — |
| Alpine v3.12 | curl | 7.79.0-r0 | — |
| Alpine v3.11 | curl | 7.79.0-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | curl +2 | 7.79.1-1.amzn2.0.1 | ALAS2-2021-1724 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | curl | 7.82.0-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | curl +3 | 7.61.1-18.el8_4.2 | ELSA-2021-4059 |
Advisories 30
- SSA-398330 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 Siemens ProductCERT · Oct 13, 2026
- RHSA-2022:1354 Red Hat Security Advisory: rh-dotnet31-curl security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- WID-SEC-2023-1350 Splunk Splunk Enterprise: Mehrere Schwachstellen in Komponenten von Drittanbietern BSI CERT-Bund (WID) · Jul 1, 2026
- USN-5079-2 curl vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- RHSA-2022:0635 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- RHSA-2021:4059 Red Hat Security Advisory: curl security update Red Hat Security Advisories (RHSA) · Jun 29, 2026
- USN-5079-1 curl vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5197-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2773-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3085-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:4059 Moderate: curl security update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2024:10582-1 curl-7.79.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3351-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3298-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14807-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3332-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1384-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:3298-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:3297-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2026-0180 Dell Data Protection Advisor: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jan 20, 2026
- WID-SEC-2023-2229 Splunk Splunk Enterprise: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 18, 2025
- WID-SEC-2022-0875 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 6, 2025
- ICSA-23-348-10 Siemens SIMATIC S7-1500 CISA ICS & IT advisories · Aug 12, 2025
- VDE-2022-010 PHOENIX CONTACT: Multiple Linux component vulnerabilities fixed in latest AXC F x152 LTS release CERT@VDE · May 22, 2025
- ICSA-22-069-09 Siemens SINEC INS CISA ICS & IT advisories · May 6, 2025
- WID-SEC-2022-1056 Apple macOS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 21, 2023
- WID-SEC-2022-1461 IBM Spectrum Protect: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 20, 2023
- SSA-389290 SSA-389290: Third-Party Component Vulnerabilities in SINEC INS Siemens ProductCERT · Mar 8, 2022
- ALAS2-2021-1724 Moderate: curl security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Dec 9, 2021
- ELSA-2021-4059 Moderate: curl security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 2, 2021
References
- https://hackerone.com/reports/1334763
- [debian-lts-announce] 20210930 [SECURITY] [DLA 2773-1] curl security update mailing-list
- FEDORA-2021-fc96a3a749 vendor-advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html
- FEDORA-2021-1d24845e93 vendor-advisory
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://security.netapp.com/advisory/ntap-20211029-0003/
- 20220314 APPLE-SA-2022-03-14-4 macOS Monterey 12.3 mailing-list
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- https://support.apple.com/kb/HT213183
- https://www.oracle.com/security-alerts/cpujul2022.html
- DSA-5197 vendor-advisory
- [debian-lts-announce] 20220828 [SECURITY] [DLA 3085-1] curl security update mailing-list
- GLSA-202212-01 vendor-advisory