How severe is CVE-2025-57783?

CVE-2025-57783 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-2025-57783 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-57783?

CVE-2025-57783 affects Hiawatha-webserver Hiawatha. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-57783?

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

Does CVE-2025-57783 have an EU (EUVD) identifier?

Yes. CVE-2025-57783 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206340.

When was CVE-2025-57783 published?

CVE-2025-57783 was published on 2026-01-26 and last updated on 2026-06-17.

CVE-2025-57783

CVE-2025-57783 is a medium-severity vulnerability in Hiawatha-webserver Hiawatha 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.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-206340
Affected product: Hiawatha-webserver Hiawatha
Published: 2026-01-26
Last modified: 2026-06-17

Description

Improper header parsing may lead to request smuggling has been identified in Hiawatha webserver version 11.7 which allows an unauthenticated attacker to access restricted resources managed by Hiawatha webserver.

Frequently asked questions

What is CVE-2025-57783?: Improper header parsing may lead to request smuggling has been identified in Hiawatha webserver version 11.7 which allows an unauthenticated attacker to access restricted resources managed by Hiawatha webserver.
How severe is CVE-2025-57783?: CVE-2025-57783 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-2025-57783 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-57783?: CVE-2025-57783 affects Hiawatha-webserver Hiawatha. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-57783?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-57783 have an EU (EUVD) identifier?: Yes. CVE-2025-57783 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206340.
When was CVE-2025-57783 published?: CVE-2025-57783 was published on 2026-01-26 and last updated on 2026-06-17.

References

https://gitlab.com/hsleisink/hiawatha/-/blame/master/src/http.c?ref_type=heads#L205

Affected products (1)

cpe:2.3:a:hiawatha-webserver:hiawatha:11.7:*:*:*:*:*:*:*

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