How severe is CVE-2026-43982?

CVE-2026-43982 has a CVSS 4.0 base score of 8.7, rated high severity.

Is CVE-2026-43982 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43982?

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.

Does CVE-2026-43982 have an EU (EUVD) identifier?

Yes. CVE-2026-43982 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31863.

When was CVE-2026-43982 published?

CVE-2026-43982 was published on 2026-05-26 and last updated on 2026-06-17.

CVE-2026-43982

CVE-2026-43982 is a high-severity vulnerability with a CVSS 4.0 base score of 8.7. 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-22.

Key facts

Severity: High (CVSS 4.0 base score 8.7)
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31863
Weakness: CWE-22
Published: 2026-05-26
Last modified: 2026-06-17

Description

Algernon is a small self-contained pure-Go web server. Prior to 1.17.6, uploadedFileSaveIn() in lua/upload/upload.go uses filepath.Join() with the caller-supplied directory but performs no boundary check after joining. A directory of ../../../tmp resolves cleanly to /tmp, outside the web root. This vulnerability is fixed in 1.17.6.

Frequently asked questions

What is CVE-2026-43982?: Algernon is a small self-contained pure-Go web server. Prior to 1.17.6, uploadedFileSaveIn() in lua/upload/upload.go uses filepath.Join() with the caller-supplied directory but performs no boundary check after joining. A directory of ../../../tmp resolves cleanly to /tmp, outside the web root. This vulnerability is fixed in 1.17.6.
How severe is CVE-2026-43982?: CVE-2026-43982 has a CVSS 4.0 base score of 8.7, rated high severity.
Is CVE-2026-43982 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-43982?: 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.
Does CVE-2026-43982 have an EU (EUVD) identifier?: Yes. CVE-2026-43982 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31863.
When was CVE-2026-43982 published?: CVE-2026-43982 was published on 2026-05-26 and last updated on 2026-06-17.

References

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