CVE-2025-57783: Improper header parsing may lead to request smuggling has been identified in Hiawatha webserver version 11.7 w

Routine

MEDIUM 5.3REMOTEDOWNGRADE

CVE-2025-57783 is a medium-severity flaw (CVSS 5.3) affecting hiawatha. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Published	2026-01-26
Last modified	2026-06-17

Publisher (CNA): CERT/CC · Vendor: hiawatha-webserver

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-01-26 18:16 UTCPublished CVE record published
2026-06-17 09:43 UTCUpdated Record last modified

hiawatha-webserver hiawatha DOWNGRADE

Affected: 11.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.7

1. Check installed version

apt-cache policy hiawatha || rpm -q hiawatha || hiawatha --version

2. No fixed release: DOWNGRADE to a release before 11.7 (Debian / Ubuntu)

apt-cache madison hiawatha sudo apt install hiawatha=<VERSION_BEFORE_11.7> sudo apt-mark hold hiawatha

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list hiawatha sudo dnf downgrade hiawatha-<VERSION_BEFORE_11.7> sudo dnf versionlock add hiawatha

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-57783?

hiawatha: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-57783 being exploited?

CVE-2025-57783 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-57783 affect?

CVE-2025-57783 affects hiawatha. Severity is medium (CVSS 5.3). 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 urgent is CVE-2025-57783?

Priority 34/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-57784 LOW 3.3 DOWNGRADE Tomahawk auth timing attack due to usage of `strcmp` has been identified in Hiawatha webserver version 11.7 wh

References

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