CVE & CISA-KEV Catalog

CVE-2023-27538

MEDIUM
5.5
CVSS v3
NVD

Description

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.

How to fix

Remediation Available
curlDebian
Fixed in:7.74.0-1.3+deb11u8CVE-2023-27538
Fixed in:7.88.1-7CVE-2023-27538
Fixed in:7.88.1-7CVE-2023-27538
Fixed in:7.88.1-7CVE-2023-27538
curlRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curlRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-debuginfoRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-debuginfoRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-debugsourceRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-debugsourceRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-minimalRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-minimalRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-minimal-debuginfoRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curl-minimal-debuginfoRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurlRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurlRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-debuginfoRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-debuginfoRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-develRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-develRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-minimalRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-minimalRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-minimal-debuginfoRocky
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
libcurl-minimal-debuginfoRed Hat / RHEL
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
Fixed in:0:7.76.1-26.el9RHSA-2023:6679
curlUbuntu
Fixed in:7.58.0-2ubuntu3.24USN-5964-1
Fixed in:7.68.0-1ubuntu2.18USN-5964-1
Fixed in:7.81.0-1ubuntu1.10USN-5964-1
Fixed in:7.85.0-1ubuntu0.5USN-5964-1
libcurl3-gnutlsUbuntu
Fixed in:7.58.0-2ubuntu3.24USN-5964-1
Fixed in:7.68.0-1ubuntu2.18USN-5964-1
Fixed in:7.81.0-1ubuntu1.10USN-5964-1
Fixed in:7.85.0-1ubuntu0.5USN-5964-1
libcurl3-nssUbuntu
Fixed in:7.58.0-2ubuntu3.24USN-5964-1
Fixed in:7.68.0-1ubuntu2.18USN-5964-1
Fixed in:7.81.0-1ubuntu1.10USN-5964-1
Fixed in:7.85.0-1ubuntu0.5USN-5964-1
libcurl4Ubuntu
Fixed in:7.58.0-2ubuntu3.24USN-5964-1
Fixed in:7.68.0-1ubuntu2.18USN-5964-1
Fixed in:7.81.0-1ubuntu1.10USN-5964-1
Fixed in:7.85.0-1ubuntu0.5USN-5964-1
UniversalForwarderWindows application
Affected:8.2.0 8.2.12Fixed in:8.2.12Splunk, Inc.
Affected:9.0.0 9.0.6Fixed in:9.0.6Splunk, Inc.

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityNone
AvailabilityNone

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Exploit Intelligence

1.16%probability of exploitation in 30 days
63rdpercentile

Moderate risk: more likely to be exploited than 63% of all known CVEs.

References

Embed a live status badge for CVE-2023-27538
CVE-2023-27538 severity badge

Markdown

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HTML

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-06-09.