How severe is CVE-2026-3783?

CVE-2026-3783 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-3783 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-3783?

CVE-2026-3783 affects Haxx Curl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-3783?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-3783 have an EU (EUVD) identifier?

Yes. CVE-2026-3783 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11138.

When was CVE-2026-3783 published?

CVE-2026-3783 was published on 2026-03-11 and last updated on 2026-06-17.

CVE-2026-3783

CVE-2026-3783 is a medium-severity vulnerability in Haxx Curl with a CVSS 3.x base score of 5.3. 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-522.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-11138
Weakness: CWE-522
Affected product: Haxx Curl
Published: 2026-03-11
Last modified: 2026-06-17

Description

When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is redirected to has information in the used .netrc file, with either of the `machine` or `default` keywords, curl would pass on the bearer token set for the first host also to the second one.

Frequently asked questions

What is CVE-2026-3783?: When an OAuth2 bearer token is used for an HTTP(S) transfer, and that transfer performs a redirect to a second URL, curl could leak that token to the second hostname under some circumstances. If the hostname that the first request is redirected to has information in the used .netrc file, with either of the `machine` or `default` keywords, curl would pass on the bearer token set for the first host also to the second one.
How severe is CVE-2026-3783?: CVE-2026-3783 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-3783 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-3783?: CVE-2026-3783 affects Haxx Curl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-3783?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-3783 have an EU (EUVD) identifier?: Yes. CVE-2026-3783 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11138.
When was CVE-2026-3783 published?: CVE-2026-3783 was published on 2026-03-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

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