CVE-2021-41615: websda.c in GoAhead WebServer 2.1.8 has insufficient nonce entropy because the nonce calculation relies on the

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-41615 is a critical-severity flaw (CVSS 9.8) affecting goahead. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

websda.c in GoAhead WebServer 2.1.8 has insufficient nonce entropy because the nonce calculation relies on the hardcoded onceuponatimeinparadise value, which does not follow the secret-data guideline for HTTP Digest Access Authentication in RFC 7616 section 3.3 (or RFC 2617 section 3.2.1). NOTE: 2.1.8 is a version from 2003; however, the affected websda.c code appears in multiple derivative works that may be used in 2021. Recent GoAhead software

Why this priority

Critical severity
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-331
Published	2022-08-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: embedthis

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

Am I affected?

Timeline

2022-08-08 19:15 UTCPublished CVE record published
2026-06-17 04:08 UTCUpdated Record last modified

embedthis goahead DOWNGRADE

Affected: 2.1.8

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.1.8

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 2.1.8 (Debian / Ubuntu)

apt-cache madison goahead sudo apt install goahead=<VERSION_BEFORE_2.1.8> sudo apt-mark hold goahead

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

dnf --showduplicates list goahead sudo dnf downgrade goahead-<VERSION_BEFORE_2.1.8> sudo dnf versionlock add goahead

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-2021-41615?

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

Is CVE-2021-41615 being exploited?

CVE-2021-41615 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-2021-41615 affect?

CVE-2021-41615 affects goahead. Severity is critical (CVSS 9.8). websda.c in GoAhead WebServer 2.1.8 has insufficient nonce entropy because the nonce calculation relies on the hardcoded onceuponatimeinparadise value, which does not follow the secret-data guideline for HTTP Digest Access Authentication in

How urgent is CVE-2021-41615?

Priority 57/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-43298 CRITICAL 9.8 UPGRADE The code that performs password matching when using 'Basic' HTTP authentication does not use a constant-time m
CVE-2021-42342 CRITICAL 9.8 UPGRADE An issue was discovered in GoAhead 4.x and 5.x before 5.1.5
CVE-2020-15688 HIGH 8.8 UPGRADE The HTTP Digest Authentication in the GoAhead web server before 5.1.2 does not completely protect against repl

References

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