How severe is CVE-2026-55874?

CVE-2026-55874 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-55874 being actively exploited?

It is not currently listed in CISA's Known Exploited Vulnerabilities catalog, and no EPSS exploit-prediction score is available yet.

How do I fix CVE-2026-55874?

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.

When was CVE-2026-55874 published?

CVE-2026-55874 was published on 2026-07-08.

CVE-2026-55874

CVE-2026-55874 is a high-severity vulnerability with a CVSS 3.x base score of 7.7. The underlying weakness is classified as CWE-22.

Key facts

Severity: High (CVSS 3.x base score 7.7)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Published: 2026-07-08
Last modified: 2026-07-08

Description

SeaweedFS is a distributed storage system. Prior to 4.34, the S3 API gateway does not reject dot-dot path segments in the X-Amz-Copy-Source header used by CopyObject and UploadPartCopy, allowing an authenticated identity scoped to one bucket to read objects from other buckets through server-side copy. This issue is fixed in version 4.34.

Frequently asked questions

What is CVE-2026-55874?: SeaweedFS is a distributed storage system. Prior to 4.34, the S3 API gateway does not reject dot-dot path segments in the X-Amz-Copy-Source header used by CopyObject and UploadPartCopy, allowing an authenticated identity scoped to one bucket to read objects from other buckets through server-side copy. This issue is fixed in version 4.34.
How severe is CVE-2026-55874?: CVE-2026-55874 has a CVSS 3.x base score of 7.7, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-55874 being actively exploited?: It is not currently listed in CISA's Known Exploited Vulnerabilities catalog, and no EPSS exploit-prediction score is available yet.
How do I fix CVE-2026-55874?: 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.
When was CVE-2026-55874 published?: CVE-2026-55874 was published on 2026-07-08.

References

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