Description
curl 7.7 through 7.76.1 suffers from an information disclosure when the `-t` command line option, known as `CURLOPT_TELNETOPTIONS` in libcurl, is used to send variable=content pairs to TELNET servers. Due to a flaw in the option parser for sending NEW_ENV variables, libcurl could be made to pass on uninitialized data from a stack based buffer to the server, resulting in potentially revealing sensitive internal information to the server using a clear-text network protocol.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | https://github.com/curl/curl | 7.7 through 7.76.1 | — |
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+deb9u15 | DLA-2734-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | curl | 7.68.0-1ubuntu2.6 | USN-5021-1 |
| Ubuntu 18.04 LTS | curl | 7.58.0-2ubuntu3.14 | USN-5021-1 |
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+esm3 | USN-5894-1, USN-5021-2 |
| Ubuntu Pro 14.04 LTS | curl | 7.35.0-1ubuntu2.20+esm14 | USN-5894-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | curl +3 | 7.61.1-22.el8 | RHSA-2021:4511 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | curl +3 | 7.61.1-22.el8 | ALSA-2021:4511 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | curl | 7.61.1-22.el8 | RLSA-2021:4511 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | curl | 7.66.0-4.17.1 | SUSE-SU-2021:1762-1 |
| SLES 15 SP2 | curl | 7.66.0-4.17.1 | SUSE-SU-2021:1762-1 |
| SLES 15 SP1 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SLES 15 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SLES 12 SP5 | curl | 7.60.0-11.18.1 | SUSE-SU-2021:1763-1 |
Show 17 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP4 | curl | 7.60.0-4.20.1 | SUSE-SU-2021:1786-1 |
| SLES 11 SP4 | curl | 7.37.0-70.66.1 | SUSE-SU-2021:14760-1 |
| SLES 11 | curl-openssl1 | 7.37.0-70.63.1 | SUSE-SU-2021:14760-1, SUSE-SU-2021:14735-1 |
| SLES for SAP 15 SP1 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SLES for SAP 15 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SLES for SAP 12 SP5 | curl | 7.60.0-11.18.1 | SUSE-SU-2021:1763-1 |
| SLES for SAP 12 SP4 | curl | 7.60.0-4.20.1 | SUSE-SU-2021:1786-1 |
| SLE Micro 5.0 | curl | 7.66.0-4.17.1 | SUSE-SU-2021:1762-1 |
| SLE HPC 15 SP1 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SLE HPC 15 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SUSE OpenStack Cloud Crowbar 9 | curl | 7.60.0-4.20.1 | SUSE-SU-2021:1786-1 |
| SUSE OpenStack Cloud 9 | curl | 7.60.0-4.20.1 | SUSE-SU-2021:1786-1 |
| SUSE Manager Server 4.0 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SUSE Manager Retail Branch Server 4.0 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SUSE Manager Proxy 4.0 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | curl | 7.37.0-70.66.1 | SUSE-SU-2021:14760-1 |
| SUSE Enterprise Storage 6 | curl | 7.60.0-3.42.1 | SUSE-SU-2021:1809-1 |
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 +1 | 7.66.0-4.17.1 | openSUSE-SU-2021:1762-1 |
| openSUSE Leap 15.2 | curl +1 | 7.66.0-lp152.3.18.1 | openSUSE-SU-2021:0808-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 7.77.0-r0 | — |
| Alpine v3.23 | curl | 7.77.0-r0 | — |
| Alpine v3.22 | curl | 7.77.0-r0 | — |
| Alpine v3.21 | curl | 7.77.0-r0 | — |
| Alpine v3.20 | curl | 7.77.0-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | curl | 7.77.0-r0 | — |
| Alpine v3.18 | curl | 7.77.0-r0 | — |
| Alpine v3.17 | curl | 7.77.0-r0 | — |
| Alpine v3.16 | curl | 7.77.0-r0 | — |
| Alpine v3.15 | curl | 7.77.0-r0 | — |
| Alpine v3.14 | curl | 7.77.0-r0 | — |
| Alpine v3.13 | curl | 7.77.0-r0 | — |
| Alpine v3.12 | curl | 7.77.0-r0 | — |
| Alpine v3.11 | curl | 7.67.0-r4 | — |
| Alpine v3.10 | curl | 7.66.0-r4 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | curl +2 | 7.61.1-12.amzn2.0.4 | ALAS2-2021-1653 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | curl | 7.76.0-5 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | curl +3 | 7.61.1-22.el8 | ELSA-2021-4511 |
Advisories 29
- ALSA-2021:4511 Moderate: curl security and bug fix update AlmaLinux Security Advisories · Oct 29, 2026
- 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-2021:4511 Red Hat Security Advisory: curl security and bug fix 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-5894-1 curl vulnerabilities Ubuntu Security Notices (USN) · Jun 29, 2026
- USN-5021-2 curl vulnerability Ubuntu Security Notices (USN) · Jun 25, 2026
- USN-5021-1 curl vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DSA-5197-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2734-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-3085-1 curl - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:4511 Moderate: curl security and bug fix update Rocky Linux Security Advisories · Feb 4, 2026
- openSUSE-SU-2024:10582-1 curl-7.79.1-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1786-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1762-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1762-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:14760-1 Security update for curl SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:1763-1 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-2022-0873 cURL und libcurl: 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
- openSUSE-SU-2021:0808-1 Security update for curl SUSE / openSUSE Security Updates · May 7, 2025
- ICSA-22-069-09 Siemens SINEC INS CISA ICS & IT advisories · May 6, 2025
- SUSE-SU-2021:1809-1 Security update for curl SUSE / openSUSE Security Updates · May 2, 2025
- SUSE-SU-2021:14735-1 Security update for curl SUSE / openSUSE Security Updates · May 2, 2025
- SSA-389290 SSA-389290: Third-Party Component Vulnerabilities in SINEC INS Siemens ProductCERT · Mar 8, 2022
- ELSA-2021-4511 Moderate: curl security and bug fix update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 16, 2021
- ALAS2-2021-1653 Moderate: curl security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jun 22, 2021
References
- https://hackerone.com/reports/1176461
- https://curl.se/docs/CVE-2021-22898.html
- https://github.com/curl/curl/commit/39ce47f219b09c380b81f89fe54ac586c8db6bde
- [guacamole-issues] 20210618 [jira] [Created] (GUACAMOLE-1368) Latest docker image fails security scans. mailing-list
- https://www.oracle.com//security-alerts/cpujul2021.html
- [oss-security] 20210721 [SECURITY ADVISORY] curl: TELNET stack contents disclosure again mailing-list
- FEDORA-2021-83fdddca0f vendor-advisory
- FEDORA-2021-5d21b90a30 vendor-advisory
- [debian-lts-announce] 20210813 [SECURITY] [DLA 2734-1] curl security update mailing-list
- https://www.oracle.com/security-alerts/cpujan2022.html
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf
- DSA-5197 vendor-advisory
- [debian-lts-announce] 20220828 [SECURITY] [DLA 3085-1] curl security update mailing-list