How severe is CVE-2016-0755?

CVE-2016-0755 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2016-0755 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-0755?

CVE-2016-0755 primarily affects Haxx Curl. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-0755?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2016-0755 published?

CVE-2016-0755 was published on 2016-01-29 and last updated on 2026-06-17.

CVE-2016-0755

CVE-2016-0755 is a high-severity vulnerability in Haxx Curl with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: High (CVSS 3.x base score 7.3)
CVSS v2: 5.0
EPSS exploit prediction: 9% (95th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Haxx Curl
Published: 2016-01-29
Last modified: 2026-06-17

Description

The ConnectionExists function in lib/url.c in libcurl before 7.47.0 does not properly re-use NTLM-authenticated proxy connections, which might allow remote attackers to authenticate as other users via a request, a similar issue to CVE-2014-0015.

Frequently asked questions

What is CVE-2016-0755?: The ConnectionExists function in lib/url.c in libcurl before 7.47.0 does not properly re-use NTLM-authenticated proxy connections, which might allow remote attackers to authenticate as other users via a request, a similar issue to CVE-2014-0015.
How severe is CVE-2016-0755?: CVE-2016-0755 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2016-0755 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (95th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-0755?: CVE-2016-0755 primarily affects Haxx Curl. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-0755?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-0755 published?: CVE-2016-0755 was published on 2016-01-29 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:15.04:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:15.10:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*

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Other CWE-287 (Improper Authentication) vulnerabilities

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CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
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