Authentication bypass in https://github.com/curl/curl
Priority LOW 37CWE-305Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 3 fixed, 3 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-287.
Summary
An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01451 73rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial Red Hat: 2 advisoriesRed Hat: 3 fixed, 3 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | https://github.com/curl/curl | Fixed in 8.0.0 | — | No fix listed | CNA |
- https://github.com/curl/curl Vendor— Affected Fixed in 8.0.0 Fixed in — No fix listed CNA
CPE configurations NVD · 16
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:haxx:libcurl:*:*:*:*:*:*:*:* | 7.16.1 to before 8.0.0 | Vulnerable | Haxx |
| cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* | 36 | Vulnerable | Fedoraproject |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
| cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:a:netapp:clustered_data_ontap:9.0:-:*:*:*:*:*:* | 9.0 | Vulnerable | NetApp |
| cpe:2.3:o:broadcom:brocade_fabric_operating_system_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Broadcom |
| cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
- cpe:2.3:a:haxx:libcurl:*:*:*:*:*:*:*:* Versions 7.16.1 to before 8.0.0 Vulnerable ·Haxx
- cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
- cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:a:netapp:clustered_data_ontap:9.0:-:*:*:*:*:*:* Versions 9.0 Vulnerable ·NetApp
- cpe:2.3:o:broadcom:brocade_fabric_operating_system_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Broadcom
- cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
Show 6 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:* | 8.2.0 to before 8.2.12; 9.0.0 to before 9.0.6 | Vulnerable | Splunk |
| cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:* | 9.1.0 | Vulnerable | Splunk |
- cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:a:splunk:universal_forwarder:*:*:*:*:*:*:*:* Versions 8.2.0 to before 8.2.12; 9.0.0 to before 9.0.6 Vulnerable ·Splunk
- cpe:2.3:a:splunk:universal_forwarder:9.1.0:*:*:*:*:*:*:* Versions 9.1.0 Vulnerable ·Splunk
Remediation
Red Hat 2 advisories
- RHSA-2023:6679 Released 2023-11-07 · Red Hat rating Moderatecurl security update
- Red Hat Enterprise Linux AppStream (v. 9) libcurl-devel-7.76.1-26.el9
- Red Hat Enterprise Linux BaseOS (v. 9) curl-7.76.1-26.el9, curl-minimal-7.76.1-26.el9, libcurl-7.76.1-26.el9 +1
- RHSA-2023:3355 Released 2023-06-05 · Red Hat rating ImportantRed Hat JBoss Core Services Apache HTTP Server 2.4.51 SP2 security update
- JBCS httpd 2.4.51.sp2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| .NET Core 3.1 on Red Hat Enterprise Linux | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
| JBCS httpd 2.4.51.sp2 | Fixed | RHSA-2023:3355 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2023:6679 |
| Red Hat Enterprise Linux BaseOS (v. 9) | Fixed | RHSA-2023:6679 |
Not affected: 1 product
- Red Hat Enterprise Linux 8
Timeline
- 2026-10-02 Threatist record created from CVE-2023-27538
- 2026-10-03 Alias added: GHSA-cgj3-cvg6-pcvh
- 2026-10-09 Fix available: RHSA-2023:3355 · Red Hat
- 2026-10-16 Fix available: JBCS httpd 2.4.51.sp2 · Red Hat
References
Sources
- CVE-2023-27538 · CVE Program
- CVE-2023-27538 · NVD
- FIRST EPSS
- GHSA-cgj3-cvg6-pcvh · GitHub Advisory Database · CC BY 4.0
- CVE-2023-27538 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences